From: Andrew Kilroy <[email protected]>
Since the size is already printed earlier in hex, print the same data
using the same format, in hex.
Reviewed-by: James Clark <[email protected]>
Signed-off-by: Andrew Kilroy <[email protected]>
Signed-off-by: German Gomez <[email protected]>
---
tools/perf/util/cs-etm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index f323adb1af85..4f672f7d008c 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -537,7 +537,7 @@ static void cs_etm__dump_event(struct cs_etm_queue *etmq,
fprintf(stdout, "\n");
color_fprintf(stdout, color,
- ". ... CoreSight %s Trace data: size %zu bytes\n",
+ ". ... CoreSight %s Trace data: size %#zx bytes\n",
cs_etm_decoder__get_name(etmq->decoder), buffer->size);
do {
--
2.17.1
From: Andrew Kilroy <[email protected]>
Since the size is already printed earlier in hex, print the same data
using the same format, in hex.
Reviewed-by: James Clark <[email protected]>
Signed-off-by: Andrew Kilroy <[email protected]>
Signed-off-by: German Gomez <[email protected]>
---
tools/perf/util/arm-spe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index 58b7069c5a5f..2196291976d9 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -100,7 +100,7 @@ static void arm_spe_dump(struct arm_spe *spe __maybe_unused,
const char *color = PERF_COLOR_BLUE;
color_fprintf(stdout, color,
- ". ... ARM SPE data: size %zu bytes\n",
+ ". ... ARM SPE data: size %#zx bytes\n",
len);
while (len) {
--
2.17.1
The head pointer of the AUX buffer managed by the arm_spe_pmu.c driver
is not monotonically increasing, therefore the find_snapshot callback is
needed in order to find the trace data within the AUX buffer and avoid
wasting space in the perf.data file.
The pointer is assumed to have wrapped if the buffer contains non-zero
data at the end. If it has wrapped, the entire contents of the AUX
buffer are stored in the perf.data file. Otherwise only the data up to
the head pointer is stored.
Reviewed-by: James Clark <[email protected]>
Signed-off-by: German Gomez <[email protected]>
---
tools/perf/arch/arm64/util/arm-spe.c | 145 +++++++++++++++++++++++++++
1 file changed, 145 insertions(+)
diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
index f8b03d164b42..56785034fc84 100644
--- a/tools/perf/arch/arm64/util/arm-spe.c
+++ b/tools/perf/arch/arm64/util/arm-spe.c
@@ -23,6 +23,7 @@
#include "../../../util/auxtrace.h"
#include "../../../util/record.h"
#include "../../../util/arm-spe.h"
+#include <tools/libc_compat.h> // reallocarray
#define KiB(x) ((x) * 1024)
#define MiB(x) ((x) * 1024 * 1024)
@@ -31,6 +32,8 @@ struct arm_spe_recording {
struct auxtrace_record itr;
struct perf_pmu *arm_spe_pmu;
struct evlist *evlist;
+ int wrapped_cnt;
+ bool *wrapped;
};
static void arm_spe_set_timestamp(struct auxtrace_record *itr,
@@ -299,6 +302,146 @@ static int arm_spe_snapshot_finish(struct auxtrace_record *itr)
return -EINVAL;
}
+static int arm_spe_alloc_wrapped_array(struct arm_spe_recording *ptr, int idx)
+{
+ bool *wrapped;
+ int cnt = ptr->wrapped_cnt, new_cnt, i;
+
+ /*
+ * No need to allocate, so return early.
+ */
+ if (idx < cnt)
+ return 0;
+
+ /*
+ * Make ptr->wrapped as big as idx.
+ */
+ new_cnt = idx + 1;
+
+ /*
+ * Free'ed in arm_spe_recording_free().
+ */
+ wrapped = reallocarray(ptr->wrapped, new_cnt, sizeof(bool));
+ if (!wrapped)
+ return -ENOMEM;
+
+ /*
+ * init new allocated values.
+ */
+ for (i = cnt; i < new_cnt; i++)
+ wrapped[i] = false;
+
+ ptr->wrapped_cnt = new_cnt;
+ ptr->wrapped = wrapped;
+
+ return 0;
+}
+
+static bool arm_spe_buffer_has_wrapped(unsigned char *buffer,
+ size_t buffer_size, u64 head)
+{
+ u64 i, watermark;
+ u64 *buf = (u64 *)buffer;
+ size_t buf_size = buffer_size;
+
+ /*
+ * Defensively handle the case where head might be continually increasing - if its value is
+ * equal or greater than the size of the ring buffer, then we can safely determine it has
+ * wrapped around. Otherwise, continue to detect if head might have wrapped.
+ */
+ if (head >= buffer_size)
+ return true;
+
+ /*
+ * We want to look the very last 512 byte (chosen arbitrarily) in the ring buffer.
+ */
+ watermark = buf_size - 512;
+
+ /*
+ * The value of head is somewhere within the size of the ring buffer. This can be that there
+ * hasn't been enough data to fill the ring buffer yet or the trace time was so long that
+ * head has numerically wrapped around. To find we need to check if we have data at the
+ * very end of the ring buffer. We can reliably do this because mmap'ed pages are zeroed
+ * out and there is a fresh mapping with every new session.
+ */
+
+ /*
+ * head is less than 512 byte from the end of the ring buffer.
+ */
+ if (head > watermark)
+ watermark = head;
+
+ /*
+ * Speed things up by using 64 bit transactions (see "u64 *buf" above)
+ */
+ watermark /= sizeof(u64);
+ buf_size /= sizeof(u64);
+
+ /*
+ * If we find trace data at the end of the ring buffer, head has been there and has
+ * numerically wrapped around at least once.
+ */
+ for (i = watermark; i < buf_size; i++)
+ if (buf[i])
+ return true;
+
+ return false;
+}
+
+static int arm_spe_find_snapshot(struct auxtrace_record *itr, int idx,
+ struct auxtrace_mmap *mm, unsigned char *data,
+ u64 *head, u64 *old)
+{
+ int err;
+ bool wrapped;
+ struct arm_spe_recording *ptr =
+ container_of(itr, struct arm_spe_recording, itr);
+
+ /*
+ * Allocate memory to keep track of wrapping if this is the first
+ * time we deal with this *mm.
+ */
+ if (idx >= ptr->wrapped_cnt) {
+ err = arm_spe_alloc_wrapped_array(ptr, idx);
+ if (err)
+ return err;
+ }
+
+ /*
+ * Check to see if *head has wrapped around. If it hasn't only the
+ * amount of data between *head and *old is snapshot'ed to avoid
+ * bloating the perf.data file with zeros. But as soon as *head has
+ * wrapped around the entire size of the AUX ring buffer it taken.
+ */
+ wrapped = ptr->wrapped[idx];
+ if (!wrapped && arm_spe_buffer_has_wrapped(data, mm->len, *head)) {
+ wrapped = true;
+ ptr->wrapped[idx] = true;
+ }
+
+ pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
+ __func__, idx, (size_t)*old, (size_t)*head, mm->len);
+
+ /*
+ * No wrap has occurred, we can just use *head and *old.
+ */
+ if (!wrapped)
+ return 0;
+
+ /*
+ * *head has wrapped around - adjust *head and *old to pickup the
+ * entire content of the AUX buffer.
+ */
+ if (*head >= mm->len) {
+ *old = *head - mm->len;
+ } else {
+ *head += mm->len;
+ *old = *head - mm->len;
+ }
+
+ return 0;
+}
+
static u64 arm_spe_reference(struct auxtrace_record *itr __maybe_unused)
{
struct timespec ts;
@@ -313,6 +456,7 @@ static void arm_spe_recording_free(struct auxtrace_record *itr)
struct arm_spe_recording *sper =
container_of(itr, struct arm_spe_recording, itr);
+ free(sper->wrapped);
free(sper);
}
@@ -336,6 +480,7 @@ struct auxtrace_record *arm_spe_recording_init(int *err,
sper->itr.pmu = arm_spe_pmu;
sper->itr.snapshot_start = arm_spe_snapshot_start;
sper->itr.snapshot_finish = arm_spe_snapshot_finish;
+ sper->itr.find_snapshot = arm_spe_find_snapshot;
sper->itr.parse_snapshot_options = arm_spe_parse_snapshot_options;
sper->itr.recording_options = arm_spe_recording_options;
sper->itr.info_priv_size = arm_spe_info_priv_size;
--
2.17.1
Shell script test_arm_spe.sh has been added to test the recording of SPE
tracing events in snapshot mode.
Reviewed-by: James Clark <[email protected]>
Signed-off-by: German Gomez <[email protected]>
---
tools/perf/tests/shell/test_arm_spe.sh | 91 ++++++++++++++++++++++++++
1 file changed, 91 insertions(+)
create mode 100755 tools/perf/tests/shell/test_arm_spe.sh
diff --git a/tools/perf/tests/shell/test_arm_spe.sh b/tools/perf/tests/shell/test_arm_spe.sh
new file mode 100755
index 000000000000..9ed817e76f95
--- /dev/null
+++ b/tools/perf/tests/shell/test_arm_spe.sh
@@ -0,0 +1,91 @@
+#!/bin/sh
+# Check Arm SPE trace data recording and synthesized samples
+
+# Uses the 'perf record' to record trace data of Arm SPE events;
+# then verify if any SPE event samples are generated by SPE with
+# 'perf script' and 'perf report' commands.
+
+# SPDX-License-Identifier: GPL-2.0
+# German Gomez <[email protected]>, 2021
+
+skip_if_no_arm_spe_event() {
+ perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
+
+ # arm_spe event doesn't exist
+ return 2
+}
+
+skip_if_no_arm_spe_event || exit 2
+
+perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+glb_err=0
+
+cleanup_files()
+{
+ rm -f ${perfdata}
+ trap - exit term int
+ kill -2 $$ # Forward sigint to parent
+ exit $glb_err
+}
+
+trap cleanup_files exit term int
+
+arm_spe_report() {
+ if [ $2 != 0 ]; then
+ echo "$1: FAIL"
+ glb_err=$2
+ else
+ echo "$1: PASS"
+ fi
+}
+
+perf_script_samples() {
+ echo "Looking at perf.data file for dumping samples:"
+
+ # from arm-spe.c/arm_spe_synth_events()
+ events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
+
+ # Below is an example of the samples dumping:
+ # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
+ # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
+ # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
+ perf script -F,-time -i ${perfdata} 2>&1 | \
+ egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
+}
+
+perf_report_samples() {
+ echo "Looking at perf.data file for reporting samples:"
+
+ # Below is an example of the samples reporting:
+ # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
+ # 7.71% 7.71% dd libc-2.27.so [.] getenv
+ # 2.59% 2.59% dd ld-2.27.so [.] strcmp
+ perf report --stdio -i ${perfdata} 2>&1 | \
+ egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
+}
+
+arm_spe_snapshot_test() {
+ echo "Recording trace with snapshot mode $perfdata"
+ perf record -o ${perfdata} -e arm_spe// -S \
+ -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
+ PERFPID=$!
+
+ # Wait for perf program
+ sleep 1
+
+ # Send signal to snapshot trace data
+ kill -USR2 $PERFPID
+
+ # Stop perf program
+ kill $PERFPID
+ wait $PERFPID
+
+ perf_script_samples dd &&
+ perf_report_samples dd
+
+ err=$?
+ arm_spe_report "SPE snapshot testing" $err
+}
+
+arm_spe_snapshot_test
+exit $glb_err
\ No newline at end of file
--
2.17.1
This patch enabled support for snapshot mode of arm_spe events,
including the implementation of the necessary callbacks (excluding
find_snapshot, which is to be included in a followup commit).
Reviewed-by: James Clark <[email protected]>
Signed-off-by: German Gomez <[email protected]>
---
tools/perf/arch/arm64/util/arm-spe.c | 130 +++++++++++++++++++++++++++
1 file changed, 130 insertions(+)
diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
index a4420d4df503..f8b03d164b42 100644
--- a/tools/perf/arch/arm64/util/arm-spe.c
+++ b/tools/perf/arch/arm64/util/arm-spe.c
@@ -84,6 +84,55 @@ static int arm_spe_info_fill(struct auxtrace_record *itr,
return 0;
}
+static void
+arm_spe_snapshot_resolve_auxtrace_defaults(struct record_opts *opts,
+ bool privileged)
+{
+ /*
+ * The default snapshot size is the auxtrace mmap size. If neither auxtrace mmap size nor
+ * snapshot size is specified, then the default is 4MiB for privileged users, 128KiB for
+ * unprivileged users.
+ *
+ * The default auxtrace mmap size is 4MiB/page_size for privileged users, 128KiB for
+ * unprivileged users. If an unprivileged user does not specify mmap pages, the mmap pages
+ * will be reduced from the default 512KiB/page_size to 256KiB/page_size, otherwise the
+ * user is likely to get an error as they exceed their mlock limmit.
+ */
+
+ /*
+ * No size were given to '-S' or '-m,', so go with the default
+ */
+ if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
+ if (privileged) {
+ opts->auxtrace_mmap_pages = MiB(4) / page_size;
+ } else {
+ opts->auxtrace_mmap_pages = KiB(128) / page_size;
+ if (opts->mmap_pages == UINT_MAX)
+ opts->mmap_pages = KiB(256) / page_size;
+ }
+ } else if (!opts->auxtrace_mmap_pages && !privileged && opts->mmap_pages == UINT_MAX) {
+ opts->mmap_pages = KiB(256) / page_size;
+ }
+
+ /*
+ * '-m,xyz' was specified but no snapshot size, so make the snapshot size as big as the
+ * auxtrace mmap area.
+ */
+ if (!opts->auxtrace_snapshot_size)
+ opts->auxtrace_snapshot_size = opts->auxtrace_mmap_pages * (size_t)page_size;
+
+ /*
+ * '-Sxyz' was specified but no auxtrace mmap area, so make the auxtrace mmap area big
+ * enough to fit the requested snapshot size.
+ */
+ if (!opts->auxtrace_mmap_pages) {
+ size_t sz = opts->auxtrace_snapshot_size;
+
+ sz = round_up(sz, page_size) / page_size;
+ opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
+ }
+}
+
static int arm_spe_recording_options(struct auxtrace_record *itr,
struct evlist *evlist,
struct record_opts *opts)
@@ -115,6 +164,36 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
if (!opts->full_auxtrace)
return 0;
+ /*
+ * we are in snapshot mode.
+ */
+ if (opts->auxtrace_snapshot_mode) {
+ /*
+ * Command arguments '-Sxyz' and/or '-m,xyz' are missing, so fill those in with
+ * default values.
+ */
+ if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages)
+ arm_spe_snapshot_resolve_auxtrace_defaults(opts, privileged);
+
+ /*
+ * Snapshot size can't be bigger than the auxtrace area.
+ */
+ if (opts->auxtrace_snapshot_size > opts->auxtrace_mmap_pages * (size_t)page_size) {
+ pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
+ opts->auxtrace_snapshot_size,
+ opts->auxtrace_mmap_pages * (size_t)page_size);
+ return -EINVAL;
+ }
+
+ /*
+ * Something went wrong somewhere - this shouldn't happen.
+ */
+ if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
+ pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
+ return -EINVAL;
+ }
+ }
+
/* We are in full trace mode but '-m,xyz' wasn't specified */
if (!opts->auxtrace_mmap_pages) {
if (privileged) {
@@ -138,6 +217,9 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
}
}
+ if (opts->auxtrace_snapshot_mode)
+ pr_debug2("%sx snapshot size: %zu\n", ARM_SPE_PMU_NAME,
+ opts->auxtrace_snapshot_size);
/*
* To obtain the auxtrace buffer file descriptor, the auxtrace event
@@ -172,6 +254,51 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
return 0;
}
+static int arm_spe_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
+ struct record_opts *opts,
+ const char *str)
+{
+ unsigned long long snapshot_size = 0;
+ char *endptr;
+
+ if (str) {
+ snapshot_size = strtoull(str, &endptr, 0);
+ if (*endptr || snapshot_size > SIZE_MAX)
+ return -1;
+ }
+
+ opts->auxtrace_snapshot_mode = true;
+ opts->auxtrace_snapshot_size = snapshot_size;
+
+ return 0;
+}
+
+static int arm_spe_snapshot_start(struct auxtrace_record *itr)
+{
+ struct arm_spe_recording *ptr =
+ container_of(itr, struct arm_spe_recording, itr);
+ struct evsel *evsel;
+
+ evlist__for_each_entry(ptr->evlist, evsel) {
+ if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
+ return evsel__disable(evsel);
+ }
+ return -EINVAL;
+}
+
+static int arm_spe_snapshot_finish(struct auxtrace_record *itr)
+{
+ struct arm_spe_recording *ptr =
+ container_of(itr, struct arm_spe_recording, itr);
+ struct evsel *evsel;
+
+ evlist__for_each_entry(ptr->evlist, evsel) {
+ if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
+ return evsel__enable(evsel);
+ }
+ return -EINVAL;
+}
+
static u64 arm_spe_reference(struct auxtrace_record *itr __maybe_unused)
{
struct timespec ts;
@@ -207,6 +334,9 @@ struct auxtrace_record *arm_spe_recording_init(int *err,
sper->arm_spe_pmu = arm_spe_pmu;
sper->itr.pmu = arm_spe_pmu;
+ sper->itr.snapshot_start = arm_spe_snapshot_start;
+ sper->itr.snapshot_finish = arm_spe_snapshot_finish;
+ sper->itr.parse_snapshot_options = arm_spe_parse_snapshot_options;
sper->itr.recording_options = arm_spe_recording_options;
sper->itr.info_priv_size = arm_spe_info_priv_size;
sper->itr.info_fill = arm_spe_info_fill;
--
2.17.1
On Thu, Sep 30, 2021 at 01:09:16PM +0100, German Gomez wrote:
> Hi Mathieu,
>
> Thanks for your feedback. I will keep these points in mind for future
> submissions.
>
> On 23/09/2021 17:24, Mathieu Poirier wrote:
> > Hi German,
> >
> > On Thu, Sep 16, 2021 at 04:46:31PM +0100, German Gomez wrote:
> > > [...]
> > Reviewed-by: Mathieu Poirier <[email protected]>
> >
> > A couple of things to improve for your next interactions with the Linux community:
> >
> > 1) Using a cover letter, even for small changes, is always a good idea.
> > 2) RB tags should be picked up publicly rather than done internally and added to
> > a patchset.
> > 3) Keep patches semantically grouped. Here patches 04 and 05 have nothing to do
> > with 01, 02 and 03.
> Did you perhaps mean separating 01 and 02 from the rest? I grouped 03 to 05
> because
> they were related to snapshot mode.
Yes - you are correct. It should have been 01 and 02 in one set and the rest in
another set.
>
> Thanks,
> German
>
> >
> > Moreover Arnaldo queues changes to the perf tools but I don't see him CC'ed to
> > this patchset. As such he will not see your work. Ask James about how to
> > proceed when submitting patches to the perf tools.
> >
> > Thanks,
> > Mathieu
> >
> > > cs_etm_decoder__get_name(etmq->decoder), buffer->size);
> > > do {
> > > --
> > > 2.17.1
> > >
Hi Leo,
On 06/10/2021 10:51, Leo Yan wrote:
> On Wed, Oct 06, 2021 at 10:35:20AM +0100, German Gomez wrote:
>
> [...]
>
>>> So simply say, I think the head pointer monotonically increasing is
>>> the right thing to do in Arm SPE driver.
>> I will talk to James about how we can proceed on this.
> Thanks!
I took this offline with James and, though it looks possible to patch
the SPE driver to have a monotonically increasing head pointer in order
to simplify the handling in the perf tool, it could be a breaking change
for users of the perf_event_open syscall that currently rely on the way
it works now.
An alternative way we considered to simplify the patch is to change the
logic inside the find_snapshot callback so that it records the entire
contents of the aux buffer every time.
What do you think?
Many thanks,
German
On Mon, Oct 11, 2021 at 04:55:37PM +0100, German Gomez wrote:
> Hi Leo,
>
> On 06/10/2021 10:51, Leo Yan wrote:
> > On Wed, Oct 06, 2021 at 10:35:20AM +0100, German Gomez wrote:
> >
> > [...]
> >
> >>> So simply say, I think the head pointer monotonically increasing is
> >>> the right thing to do in Arm SPE driver.
> >> I will talk to James about how we can proceed on this.
> > Thanks!
>
> I took this offline with James and, though it looks possible to patch
> the SPE driver to have a monotonically increasing head pointer in order
> to simplify the handling in the perf tool, it could be a breaking change
> for users of the perf_event_open syscall that currently rely on the way
> it works now.
>
> An alternative way we considered to simplify the patch is to change the
> logic inside the find_snapshot callback so that it records the entire
> contents of the aux buffer every time.
>
> What do you think?
What does intel-pt do?
Will
On 12/10/2021 09:19, Will Deacon wrote:
> On Mon, Oct 11, 2021 at 04:55:37PM +0100, German Gomez wrote:
>> Hi Leo,
>>
>> On 06/10/2021 10:51, Leo Yan wrote:
>>> On Wed, Oct 06, 2021 at 10:35:20AM +0100, German Gomez wrote:
>>>
>>> [...]
>>>
>>>>> So simply say, I think the head pointer monotonically increasing is
>>>>> the right thing to do in Arm SPE driver.
>>>> I will talk to James about how we can proceed on this.
>>> Thanks!
>>
>> I took this offline with James and, though it looks possible to patch
>> the SPE driver to have a monotonically increasing head pointer in order
>> to simplify the handling in the perf tool, it could be a breaking change
>> for users of the perf_event_open syscall that currently rely on the way
>> it works now.
>>
>> An alternative way we considered to simplify the patch is to change the
>> logic inside the find_snapshot callback so that it records the entire
>> contents of the aux buffer every time.
>>
>> What do you think?
>
> What does intel-pt do?
Intel-pt has a wrapped head, which is why it has the intel_pt_find_snapshot()
function in perf to try to not save any zeros from the buffer that haven't
been written yet. (With a wrapped head pointer it's impossible to tell).
Coresight has a monotonically increasing head pointer so it is possible to
tell. Recently, Leo removed the Coresight version of find_snapshot() for this
reason.
It would be nice to do the same for SPE because that function has a heuristic
and is also slow, but I imagine that not returning wrapped head pointers could
break anything that expects them.
James
>
> Will
>
On Wed, Oct 13, 2021 at 08:39:16AM +0800, Leo Yan wrote:
> On Mon, Oct 11, 2021 at 04:55:37PM +0100, German Gomez wrote:
> > On 06/10/2021 10:51, Leo Yan wrote:
> > > On Wed, Oct 06, 2021 at 10:35:20AM +0100, German Gomez wrote:
> > >
> > > [...]
> > >
> > >>> So simply say, I think the head pointer monotonically increasing is
> > >>> the right thing to do in Arm SPE driver.
> > >> I will talk to James about how we can proceed on this.
> > > Thanks!
> >
> > I took this offline with James and, though it looks possible to patch
> > the SPE driver to have a monotonically increasing head pointer in order
> > to simplify the handling in the perf tool, it could be a breaking change
> > for users of the perf_event_open syscall that currently rely on the way
> > it works now.
>
> Here I cannot create the connection between AUX head pointer and the
> breakage of calling perf_event_open().
>
> Could you elaborate what's the reason the monotonical increasing head
> pointer will lead to the breakage for perf_event_open()?
It's a user-visible change in behaviour, isn't it? Therefore we risk
breaking applications that rely on the current behaviour if we change it
unconditionally.
Given that the driver has always worked like this and it doesn't sound like
it's the end of the world to deal with it in userspace (after all, it's
aligned with intel-pt), then I don't think we should change it.
Will
On Thu, Sep 16, 2021 at 04:46:33PM +0100, German Gomez wrote:
> This patch enabled support for snapshot mode of arm_spe events,
> including the implementation of the necessary callbacks (excluding
> find_snapshot, which is to be included in a followup commit).
>
> Reviewed-by: James Clark <[email protected]>
> Signed-off-by: German Gomez <[email protected]>
Reviewed-by: Leo Yan <[email protected]>
Tested-by: Leo Yan <[email protected]>
On Thu, Sep 16, 2021 at 04:46:35PM +0100, German Gomez wrote:
> Shell script test_arm_spe.sh has been added to test the recording of SPE
> tracing events in snapshot mode.
>
> Reviewed-by: James Clark <[email protected]>
> Signed-off-by: German Gomez <[email protected]>
> ---
> tools/perf/tests/shell/test_arm_spe.sh | 91 ++++++++++++++++++++++++++
> 1 file changed, 91 insertions(+)
> create mode 100755 tools/perf/tests/shell/test_arm_spe.sh
>
> diff --git a/tools/perf/tests/shell/test_arm_spe.sh b/tools/perf/tests/shell/test_arm_spe.sh
> new file mode 100755
> index 000000000000..9ed817e76f95
> --- /dev/null
> +++ b/tools/perf/tests/shell/test_arm_spe.sh
> @@ -0,0 +1,91 @@
> +#!/bin/sh
> +# Check Arm SPE trace data recording and synthesized samples
> +
> +# Uses the 'perf record' to record trace data of Arm SPE events;
> +# then verify if any SPE event samples are generated by SPE with
> +# 'perf script' and 'perf report' commands.
> +
> +# SPDX-License-Identifier: GPL-2.0
> +# German Gomez <[email protected]>, 2021
> +
> +skip_if_no_arm_spe_event() {
> + perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
> +
> + # arm_spe event doesn't exist
> + return 2
> +}
> +
> +skip_if_no_arm_spe_event || exit 2
> +
> +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
> +glb_err=0
> +
> +cleanup_files()
> +{
> + rm -f ${perfdata}
> + trap - exit term int
> + kill -2 $$ # Forward sigint to parent
I understand you copy this code from Arm cs-etm testing, but I found
the sentence 'kill -2 $$' will cause a failure at my side with the
command:
root@ubuntu:/home/leoy/linux/tools/perf# ./perf test 85 -v
85: Check Arm SPE trace data recording and synthesized samples :
--- start ---
test child forked, pid 29053
Recording trace with snapshot mode /tmp/__perf_test.perf.data.uughb
Looking at perf.data file for dumping samples:
Looking at perf.data file for reporting samples:
SPE snapshot testing: PASS
test child finished with -1
---- end ----
Check Arm SPE trace data recording and synthesized samples: FAILED!
I changed to use below code and looks it works for me:
if [[ "$1" == "int" ]]; then
kill -SIGINT $$
fi
if [[ "$1" == "term" ]]; then
kill -SIGTERM $$
fi
Thanks,
Leo
> + exit $glb_err
> +}
> +
> +trap cleanup_files exit term int
> +
> +arm_spe_report() {
> + if [ $2 != 0 ]; then
> + echo "$1: FAIL"
> + glb_err=$2
> + else
> + echo "$1: PASS"
> + fi
> +}
> +
> +perf_script_samples() {
> + echo "Looking at perf.data file for dumping samples:"
> +
> + # from arm-spe.c/arm_spe_synth_events()
> + events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
> +
> + # Below is an example of the samples dumping:
> + # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
> + # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
> + # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
> + perf script -F,-time -i ${perfdata} 2>&1 | \
> + egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
> +}
> +
> +perf_report_samples() {
> + echo "Looking at perf.data file for reporting samples:"
> +
> + # Below is an example of the samples reporting:
> + # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
> + # 7.71% 7.71% dd libc-2.27.so [.] getenv
> + # 2.59% 2.59% dd ld-2.27.so [.] strcmp
> + perf report --stdio -i ${perfdata} 2>&1 | \
> + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
> +}
> +
> +arm_spe_snapshot_test() {
> + echo "Recording trace with snapshot mode $perfdata"
> + perf record -o ${perfdata} -e arm_spe// -S \
> + -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
> + PERFPID=$!
> +
> + # Wait for perf program
> + sleep 1
> +
> + # Send signal to snapshot trace data
> + kill -USR2 $PERFPID
> +
> + # Stop perf program
> + kill $PERFPID
> + wait $PERFPID
> +
> + perf_script_samples dd &&
> + perf_report_samples dd
> +
> + err=$?
> + arm_spe_report "SPE snapshot testing" $err
> +}
> +
> +arm_spe_snapshot_test
> +exit $glb_err
> \ No newline at end of file
> --
> 2.17.1
>
Hi Leo,
I'm unable to reproduce. I've tried on top of the most recent perf/core
branch but I still get exit code 0 consistently:
$ git log
commit be8ecc57f180415e8a7c1cc5620c5236be2a7e56 (grafted, origin/perf/core)
Author: Tony Garnock-Jones <[email protected]>
Date: Thu Sep 16 14:09:39 2021 +0200
$ ./perf test 88 -v
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
88: Check Arm SPE trace data recording and synthesized samples :
--- start ---
test child forked, pid 18700
Recording trace with snapshot mode /tmp/__perf_test.perf.data.xgsUt
Looking at perf.data file for dumping samples:
Looking at perf.data file for reporting samples:
SPE snapshot testing: PASS
test child finished with 0
---- end ----
Check Arm SPE trace data recording and synthesized samples: Ok
On 20/10/2021 14:13, Leo Yan wrote:
> On Thu, Sep 16, 2021 at 04:46:35PM +0100, German Gomez wrote:
>> Shell script test_arm_spe.sh has been added to test the recording of SPE
>> tracing events in snapshot mode.
>>
>> Reviewed-by: James Clark <[email protected]>
>> Signed-off-by: German Gomez <[email protected]>
>> ---
>> tools/perf/tests/shell/test_arm_spe.sh | 91 ++++++++++++++++++++++++++
>> 1 file changed, 91 insertions(+)
>> create mode 100755 tools/perf/tests/shell/test_arm_spe.sh
>>
>> diff --git a/tools/perf/tests/shell/test_arm_spe.sh b/tools/perf/tests/shell/test_arm_spe.sh
>> new file mode 100755
>> index 000000000000..9ed817e76f95
>> --- /dev/null
>> +++ b/tools/perf/tests/shell/test_arm_spe.sh
>> @@ -0,0 +1,91 @@
>> +#!/bin/sh
>> +# Check Arm SPE trace data recording and synthesized samples
>> +
>> +# Uses the 'perf record' to record trace data of Arm SPE events;
>> +# then verify if any SPE event samples are generated by SPE with
>> +# 'perf script' and 'perf report' commands.
>> +
>> +# SPDX-License-Identifier: GPL-2.0
>> +# German Gomez <[email protected]>, 2021
>> +
>> +skip_if_no_arm_spe_event() {
>> + perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
>> +
>> + # arm_spe event doesn't exist
>> + return 2
>> +}
>> +
>> +skip_if_no_arm_spe_event || exit 2
>> +
>> +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
>> +glb_err=0
>> +
>> +cleanup_files()
>> +{
>> + rm -f ${perfdata}
>> + trap - exit term int
>> + kill -2 $$ # Forward sigint to parent
> I understand you copy this code from Arm cs-etm testing, but I found
> the sentence 'kill -2 $$' will cause a failure at my side with the
> command:
>
> root@ubuntu:/home/leoy/linux/tools/perf# ./perf test 85 -v
> 85: Check Arm SPE trace data recording and synthesized samples :
> --- start ---
> test child forked, pid 29053
> Recording trace with snapshot mode /tmp/__perf_test.perf.data.uughb
> Looking at perf.data file for dumping samples:
> Looking at perf.data file for reporting samples:
> SPE snapshot testing: PASS
> test child finished with -1
> ---- end ----
> Check Arm SPE trace data recording and synthesized samples: FAILED!
>
> I changed to use below code and looks it works for me:
>
> if [[ "$1" == "int" ]]; then
> kill -SIGINT $$
> fi
> if [[ "$1" == "term" ]]; then
> kill -SIGTERM $$
> fi
>
> Thanks,
> Leo
>
>> + exit $glb_err
>> +}
>> +
>> +trap cleanup_files exit term int
>> +
>> +arm_spe_report() {
>> + if [ $2 != 0 ]; then
>> + echo "$1: FAIL"
>> + glb_err=$2
>> + else
>> + echo "$1: PASS"
>> + fi
>> +}
>> +
>> +perf_script_samples() {
>> + echo "Looking at perf.data file for dumping samples:"
>> +
>> + # from arm-spe.c/arm_spe_synth_events()
>> + events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
>> +
>> + # Below is an example of the samples dumping:
>> + # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + perf script -F,-time -i ${perfdata} 2>&1 | \
>> + egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
>> +}
>> +
>> +perf_report_samples() {
>> + echo "Looking at perf.data file for reporting samples:"
>> +
>> + # Below is an example of the samples reporting:
>> + # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
>> + # 7.71% 7.71% dd libc-2.27.so [.] getenv
>> + # 2.59% 2.59% dd ld-2.27.so [.] strcmp
>> + perf report --stdio -i ${perfdata} 2>&1 | \
>> + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
>> +}
>> +
>> +arm_spe_snapshot_test() {
>> + echo "Recording trace with snapshot mode $perfdata"
>> + perf record -o ${perfdata} -e arm_spe// -S \
>> + -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
>> + PERFPID=$!
>> +
>> + # Wait for perf program
>> + sleep 1
>> +
>> + # Send signal to snapshot trace data
>> + kill -USR2 $PERFPID
>> +
>> + # Stop perf program
>> + kill $PERFPID
>> + wait $PERFPID
>> +
>> + perf_script_samples dd &&
>> + perf_report_samples dd
>> +
>> + err=$?
>> + arm_spe_report "SPE snapshot testing" $err
>> +}
>> +
>> +arm_spe_snapshot_test
>> +exit $glb_err
>> \ No newline at end of file
>> --
>> 2.17.1
>>
On 20/10/2021 14:13, Leo Yan wrote:
> On Thu, Sep 16, 2021 at 04:46:35PM +0100, German Gomez wrote:
>> Shell script test_arm_spe.sh has been added to test the recording of SPE
>> tracing events in snapshot mode.
>>
>> Reviewed-by: James Clark <[email protected]>
>> Signed-off-by: German Gomez <[email protected]>
>> ---
>> tools/perf/tests/shell/test_arm_spe.sh | 91 ++++++++++++++++++++++++++
>> 1 file changed, 91 insertions(+)
>> create mode 100755 tools/perf/tests/shell/test_arm_spe.sh
>>
>> diff --git a/tools/perf/tests/shell/test_arm_spe.sh b/tools/perf/tests/shell/test_arm_spe.sh
>> new file mode 100755
>> index 000000000000..9ed817e76f95
>> --- /dev/null
>> +++ b/tools/perf/tests/shell/test_arm_spe.sh
>> @@ -0,0 +1,91 @@
>> +#!/bin/sh
>> +# Check Arm SPE trace data recording and synthesized samples
>> +
>> +# Uses the 'perf record' to record trace data of Arm SPE events;
>> +# then verify if any SPE event samples are generated by SPE with
>> +# 'perf script' and 'perf report' commands.
>> +
>> +# SPDX-License-Identifier: GPL-2.0
>> +# German Gomez <[email protected]>, 2021
>> +
>> +skip_if_no_arm_spe_event() {
>> + perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
>> +
>> + # arm_spe event doesn't exist
>> + return 2
>> +}
>> +
>> +skip_if_no_arm_spe_event || exit 2
>> +
>> +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
>> +glb_err=0
>> +
>> +cleanup_files()
>> +{
>> + rm -f ${perfdata}
>> + trap - exit term int
>> + kill -2 $$ # Forward sigint to parent
>
> I understand you copy this code from Arm cs-etm testing, but I found
> the sentence 'kill -2 $$' will cause a failure at my side with the
> command:
>
> root@ubuntu:/home/leoy/linux/tools/perf# ./perf test 85 -v
> 85: Check Arm SPE trace data recording and synthesized samples :
> --- start ---
> test child forked, pid 29053
> Recording trace with snapshot mode /tmp/__perf_test.perf.data.uughb
> Looking at perf.data file for dumping samples:
> Looking at perf.data file for reporting samples:
> SPE snapshot testing: PASS
> test child finished with -1
> ---- end ----
> Check Arm SPE trace data recording and synthesized samples: FAILED!
>
> I changed to use below code and looks it works for me:
>
> if [[ "$1" == "int" ]]; then
> kill -SIGINT $$
> fi
> if [[ "$1" == "term" ]]; then
> kill -SIGTERM $$
> fi
>
> Thanks,
> Leo
This is quite interesting. It looks like the issue is caused by the update from dash 0.5.8
on Ubuntu 18 to dash 0.5.10 on Ubuntu 20. Specifically the commit that causes the issue is:
commit 9e5cd41d9605e4caaac3aacdc0482f6ee220a298
Author: Herbert Xu <[email protected]>
Date: Mon May 7 00:40:34 2018 +0800
jobs - Do not block when waiting on SIGCHLD
Because of the nature of SIGCHLD, the process may have already been
waited on and therefore we must be prepared for the case that wait
may block. So ensure that it doesn't by using WNOHANG.
Furthermore, multiple jobs may have exited when gotsigchld is set.
Therefore we need to wait until there are no zombies left.
Lastly, waitforjob needs to be called with interrupts off and
the original patch broke that.
Fixes: 03876c0743a5 ("eval: Reap zombies after built-in...")
Signed-off-by: Herbert Xu <[email protected]>
This also means that the Coresight shell test will not be working anymore because I added
the same trap to it so that it could be run in a loop. I'm going to compare the bahaviour
to bash to see which one is doing the right thing and what the correct change to make to
fix it is. Or a bug needs to be reported.
Thanks
James
>
>> + exit $glb_err
>> +}
>> +
>> +trap cleanup_files exit term int
>> +
>> +arm_spe_report() {
>> + if [ $2 != 0 ]; then
>> + echo "$1: FAIL"
>> + glb_err=$2
>> + else
>> + echo "$1: PASS"
>> + fi
>> +}
>> +
>> +perf_script_samples() {
>> + echo "Looking at perf.data file for dumping samples:"
>> +
>> + # from arm-spe.c/arm_spe_synth_events()
>> + events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
>> +
>> + # Below is an example of the samples dumping:
>> + # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>> + perf script -F,-time -i ${perfdata} 2>&1 | \
>> + egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
>> +}
>> +
>> +perf_report_samples() {
>> + echo "Looking at perf.data file for reporting samples:"
>> +
>> + # Below is an example of the samples reporting:
>> + # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
>> + # 7.71% 7.71% dd libc-2.27.so [.] getenv
>> + # 2.59% 2.59% dd ld-2.27.so [.] strcmp
>> + perf report --stdio -i ${perfdata} 2>&1 | \
>> + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
>> +}
>> +
>> +arm_spe_snapshot_test() {
>> + echo "Recording trace with snapshot mode $perfdata"
>> + perf record -o ${perfdata} -e arm_spe// -S \
>> + -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
>> + PERFPID=$!
>> +
>> + # Wait for perf program
>> + sleep 1
>> +
>> + # Send signal to snapshot trace data
>> + kill -USR2 $PERFPID
>> +
>> + # Stop perf program
>> + kill $PERFPID
>> + wait $PERFPID
>> +
>> + perf_script_samples dd &&
>> + perf_report_samples dd
>> +
>> + err=$?
>> + arm_spe_report "SPE snapshot testing" $err
>> +}
>> +
>> +arm_spe_snapshot_test
>> +exit $glb_err
>> \ No newline at end of file
>> --
>> 2.17.1
>>
On 02/11/2021 14:07, James Clark wrote:
>
>
> On 20/10/2021 14:13, Leo Yan wrote:
>> On Thu, Sep 16, 2021 at 04:46:35PM +0100, German Gomez wrote:
>>> Shell script test_arm_spe.sh has been added to test the recording of SPE
>>> tracing events in snapshot mode.
>>>
>>> Reviewed-by: James Clark <[email protected]>
>>> Signed-off-by: German Gomez <[email protected]>
>>> ---
>>> tools/perf/tests/shell/test_arm_spe.sh | 91 ++++++++++++++++++++++++++
>>> 1 file changed, 91 insertions(+)
>>> create mode 100755 tools/perf/tests/shell/test_arm_spe.sh
>>>
>>> diff --git a/tools/perf/tests/shell/test_arm_spe.sh b/tools/perf/tests/shell/test_arm_spe.sh
>>> new file mode 100755
>>> index 000000000000..9ed817e76f95
>>> --- /dev/null
>>> +++ b/tools/perf/tests/shell/test_arm_spe.sh
>>> @@ -0,0 +1,91 @@
>>> +#!/bin/sh
>>> +# Check Arm SPE trace data recording and synthesized samples
>>> +
>>> +# Uses the 'perf record' to record trace data of Arm SPE events;
>>> +# then verify if any SPE event samples are generated by SPE with
>>> +# 'perf script' and 'perf report' commands.
>>> +
>>> +# SPDX-License-Identifier: GPL-2.0
>>> +# German Gomez <[email protected]>, 2021
>>> +
>>> +skip_if_no_arm_spe_event() {
>>> + perf list | egrep -q 'arm_spe_[0-9]+//' && return 0
>>> +
>>> + # arm_spe event doesn't exist
>>> + return 2
>>> +}
>>> +
>>> +skip_if_no_arm_spe_event || exit 2
>>> +
>>> +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
>>> +glb_err=0
>>> +
>>> +cleanup_files()
>>> +{
>>> + rm -f ${perfdata}
>>> + trap - exit term int
>>> + kill -2 $$ # Forward sigint to parent
>>
>> I understand you copy this code from Arm cs-etm testing, but I found
>> the sentence 'kill -2 $$' will cause a failure at my side with the
>> command:
>>
>> root@ubuntu:/home/leoy/linux/tools/perf# ./perf test 85 -v
>> 85: Check Arm SPE trace data recording and synthesized samples :
>> --- start ---
>> test child forked, pid 29053
>> Recording trace with snapshot mode /tmp/__perf_test.perf.data.uughb
>> Looking at perf.data file for dumping samples:
>> Looking at perf.data file for reporting samples:
>> SPE snapshot testing: PASS
>> test child finished with -1
>> ---- end ----
>> Check Arm SPE trace data recording and synthesized samples: FAILED!
>>
>> I changed to use below code and looks it works for me:
>>
>> if [[ "$1" == "int" ]]; then
>> kill -SIGINT $$
>> fi
>> if [[ "$1" == "term" ]]; then
>> kill -SIGTERM $$
>> fi
>>
>> Thanks,
>> Leo
>
> This is quite interesting. It looks like the issue is caused by the update from dash 0.5.8
> on Ubuntu 18 to dash 0.5.10 on Ubuntu 20. Specifically the commit that causes the issue is:
>
> commit 9e5cd41d9605e4caaac3aacdc0482f6ee220a298
> Author: Herbert Xu <[email protected]>
> Date: Mon May 7 00:40:34 2018 +0800
>
> jobs - Do not block when waiting on SIGCHLD
>
> Because of the nature of SIGCHLD, the process may have already been
> waited on and therefore we must be prepared for the case that wait
> may block. So ensure that it doesn't by using WNOHANG.
>
> Furthermore, multiple jobs may have exited when gotsigchld is set.
> Therefore we need to wait until there are no zombies left.
>
> Lastly, waitforjob needs to be called with interrupts off and
> the original patch broke that.
>
> Fixes: 03876c0743a5 ("eval: Reap zombies after built-in...")
> Signed-off-by: Herbert Xu <[email protected]>
>
>
> This also means that the Coresight shell test will not be working anymore because I added
> the same trap to it so that it could be run in a loop. I'm going to compare the bahaviour
> to bash to see which one is doing the right thing and what the correct change to make to
> fix it is. Or a bug needs to be reported.
>
> Thanks
> James
>
Ok, it seems like I was relying on buggy dash behaviour for my original change. Even with this:
if [[ "$1" == "int" ]]; then
kill -SIGINT $$
fi
if [[ "$1" == "term" ]]; then
kill -SIGTERM $$
fi
it still doesn't allow you to break out of running it in a while loop. This is only because of
the exit code, rather than any kind of signal propagation. Actually it's possible to stop it
with Ctrl-\ rather than Ctrl-C, and that doesn't require any extra handling in the script.
For that reason I'm happy to go with Leo's original suggestion when I first added this which was
to not have any extra kill at all.
Another fix could be this, but I'm not too keen on it because I don't think any other tests behave
like this:
[ "$1" = "int" ] || exit 1
[ "$1" = "term" ] || exit 1
>>
>>> + exit $glb_err
>>> +}
>>> +
>>> +trap cleanup_files exit term int
>>> +
>>> +arm_spe_report() {
>>> + if [ $2 != 0 ]; then
>>> + echo "$1: FAIL"
>>> + glb_err=$2
>>> + else
>>> + echo "$1: PASS"
>>> + fi
>>> +}
>>> +
>>> +perf_script_samples() {
>>> + echo "Looking at perf.data file for dumping samples:"
>>> +
>>> + # from arm-spe.c/arm_spe_synth_events()
>>> + events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
>>> +
>>> + # Below is an example of the samples dumping:
>>> + # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>> + # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>> + # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>> + perf script -F,-time -i ${perfdata} 2>&1 | \
>>> + egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
>>> +}
>>> +
>>> +perf_report_samples() {
>>> + echo "Looking at perf.data file for reporting samples:"
>>> +
>>> + # Below is an example of the samples reporting:
>>> + # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
>>> + # 7.71% 7.71% dd libc-2.27.so [.] getenv
>>> + # 2.59% 2.59% dd ld-2.27.so [.] strcmp
>>> + perf report --stdio -i ${perfdata} 2>&1 | \
>>> + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
>>> +}
>>> +
>>> +arm_spe_snapshot_test() {
>>> + echo "Recording trace with snapshot mode $perfdata"
>>> + perf record -o ${perfdata} -e arm_spe// -S \
>>> + -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
>>> + PERFPID=$!
>>> +
>>> + # Wait for perf program
>>> + sleep 1
>>> +
>>> + # Send signal to snapshot trace data
>>> + kill -USR2 $PERFPID
>>> +
>>> + # Stop perf program
>>> + kill $PERFPID
>>> + wait $PERFPID
>>> +
>>> + perf_script_samples dd &&
>>> + perf_report_samples dd
>>> +
>>> + err=$?
>>> + arm_spe_report "SPE snapshot testing" $err
>>> +}
>>> +
>>> +arm_spe_snapshot_test
>>> +exit $glb_err
>>> \ No newline at end of file
>>> --
>>> 2.17.1
>>>
Hi James, Leo,
Thank you for testing the patch.
On 02/11/2021 15:37, James Clark wrote:
> [...]
> Ok, it seems like I was relying on buggy dash behaviour for my original change. Even with this:
>
> if [[ "$1" == "int" ]]; then
> kill -SIGINT $$
> fi
> if [[ "$1" == "term" ]]; then
> kill -SIGTERM $$
> fi
>
> it still doesn't allow you to break out of running it in a while loop. This is only because of
> the exit code, rather than any kind of signal propagation. Actually it's possible to stop it
> with Ctrl-\ rather than Ctrl-C, and that doesn't require any extra handling in the script.
>
> For that reason I'm happy to go with Leo's original suggestion when I first added this which was
> to not have any extra kill at all.
Thanks for debugging the issue, I think I will consider this fix in the
re-submission.
Thanks,
German
>
> Another fix could be this, but I'm not too keen on it because I don't think any other tests behave
> like this:
>
> [ "$1" = "int" ] || exit 1
> [ "$1" = "term" ] || exit 1
>
>>>> + exit $glb_err
>>>> +}
>>>> +
>>>> +trap cleanup_files exit term int
>>>> +
>>>> +arm_spe_report() {
>>>> + if [ $2 != 0 ]; then
>>>> + echo "$1: FAIL"
>>>> + glb_err=$2
>>>> + else
>>>> + echo "$1: PASS"
>>>> + fi
>>>> +}
>>>> +
>>>> +perf_script_samples() {
>>>> + echo "Looking at perf.data file for dumping samples:"
>>>> +
>>>> + # from arm-spe.c/arm_spe_synth_events()
>>>> + events="(ld1-miss|ld1-access|llc-miss|lld-access|tlb-miss|tlb-access|branch-miss|remote-access|memory)"
>>>> +
>>>> + # Below is an example of the samples dumping:
>>>> + # dd 3048 [002] 1 l1d-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>>> + # dd 3048 [002] 1 tlb-access: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>>> + # dd 3048 [002] 1 memory: ffffaa64999c __GI___libc_write+0x3c (/lib/aarch64-linux-gnu/libc-2.27.so)
>>>> + perf script -F,-time -i ${perfdata} 2>&1 | \
>>>> + egrep " +$1 +[0-9]+ .* +${events}:(.*:)? +" > /dev/null 2>&1
>>>> +}
>>>> +
>>>> +perf_report_samples() {
>>>> + echo "Looking at perf.data file for reporting samples:"
>>>> +
>>>> + # Below is an example of the samples reporting:
>>>> + # 73.04% 73.04% dd libc-2.27.so [.] _dl_addr
>>>> + # 7.71% 7.71% dd libc-2.27.so [.] getenv
>>>> + # 2.59% 2.59% dd ld-2.27.so [.] strcmp
>>>> + perf report --stdio -i ${perfdata} 2>&1 | \
>>>> + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > /dev/null 2>&1
>>>> +}
>>>> +
>>>> +arm_spe_snapshot_test() {
>>>> + echo "Recording trace with snapshot mode $perfdata"
>>>> + perf record -o ${perfdata} -e arm_spe// -S \
>>>> + -- dd if=/dev/zero of=/dev/null > /dev/null 2>&1 &
>>>> + PERFPID=$!
>>>> +
>>>> + # Wait for perf program
>>>> + sleep 1
>>>> +
>>>> + # Send signal to snapshot trace data
>>>> + kill -USR2 $PERFPID
>>>> +
>>>> + # Stop perf program
>>>> + kill $PERFPID
>>>> + wait $PERFPID
>>>> +
>>>> + perf_script_samples dd &&
>>>> + perf_report_samples dd
>>>> +
>>>> + err=$?
>>>> + arm_spe_report "SPE snapshot testing" $err
>>>> +}
>>>> +
>>>> +arm_spe_snapshot_test
>>>> +exit $glb_err
>>>> \ No newline at end of file
>>>> --
>>>> 2.17.1
>>>>
Hi Leo,
On 17/10/2021 07:13, Leo Yan wrote:
> [...]
>
> I looked into the Arm SPE driver and found it doesn't really support
> free run mode for AUX ring buffer when the driver runs in snapshot
> mode, the pair functions perf_aux_output_end() and
> perf_aux_output_begin() are invoked when every time handle the
> interrupt. The detailed flow is:
>
> arm_spe_pmu_irq_handler()
> `> arm_spe_pmu_buf_get_fault_act()
> `> arm_spe_perf_aux_output_end()
> `> set SPE registers
> `> perf_aux_output_end()
> `> arm_spe_perf_aux_output_begin()
> `> perf_aux_output_begin()
> `> set SPE registers
>
> Seems to me, a possible solution is to add an extra parameter 'int
> in_interrupt' for functions arm_spe_perf_aux_output_end() and
> arm_spe_perf_aux_output_begin(), if this parameter is passed as 1 in
> the interrupt handling, these two functions should skip invoking
> perf_aux_output_end() and perf_aux_output_begin() so can avoid the
> redundant perf event PERF_RECORD_AUX.
>
> arm_spe_pmu_irq_handler()
> `> arm_spe_pmu_buf_get_fault_act()
> `> arm_spe_perf_aux_output_end(..., in_interrupt=1)
> `> set SPE registers
> `> arm_spe_perf_aux_output_begin(..., in_interrupt=1)
> `> set SPE registers
I brought the issue of the redundant AUX events to the team, and we know
of at least one tool in Arm relying on these events in snapshot mode. So
we think that changing this behavior of the driver might not be easy to
do right now.
>
> P.s. I think Intel-PT has supported free run mode for snapshot mode,
> so it should not generate interrupt in this mode. Thus Intel-PT can
> avoid this issue, please see the code [2].
>
> Thanks,
> Leo
>
> [1] https://people.linaro.org/~leo.yan/spe/snapshot_test/perf.data
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/events/intel/pt.c#n753
Thanks,
German