[BUG]
For btrfs related events, there is a field for fsid, but perf never
parse it correctly.
# perf trace -e btrfs:qgroup_meta_convert xfs_io -f -c "pwrite 0 4k" \
/mnt/btrfs/file1
0.000 xfs_io/77915 btrfs:qgroup_meta_reserve:(nil)U: refroot=5(FS_TREE) type=0x0 diff=2
^^^^^^ Not a correct UUID
...
[CAUSE]
The pretty_print() function doesn't handle the %pU format correctly.
In fact it doesn't handle %pU as uuid at all.
[FIX]
Add a new function, print_uuid_arg(), to handle %pU correctly.
Now perf trace can at least print fsid correctly:
0.000 xfs_io/79619 btrfs:qgroup_meta_reserve:23ad1511-dd83-47d4-a79c-e96625a15a6e refroot=5(FS_TREE) type=0x0 diff=2
Signed-off-by: Qu Wenruo <[email protected]>
---
Changelog:
v2:
- Use more comment explaining the finetunings we skipped for %pU*
- Use more elegant way to output uuid string
---
tools/lib/traceevent/event-parse.c | 56 ++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index d948475585ce..3c9473f46efe 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -18,6 +18,7 @@
#include <errno.h>
#include <stdint.h>
#include <limits.h>
+#include <linux/uuid.h>
#include <linux/time64.h>
#include <netinet/in.h>
@@ -4508,6 +4509,45 @@ get_bprint_format(void *data, int size __maybe_unused,
return format;
}
+static void print_uuid_arg(struct trace_seq *s, void *data, int size,
+ struct tep_event *event, struct tep_print_arg *arg)
+{
+ unsigned char *buf;
+ int i;
+
+ if (arg->type != TEP_PRINT_FIELD) {
+ trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type);
+ return;
+ }
+
+ if (!arg->field.field) {
+ arg->field.field = tep_find_any_field(event, arg->field.name);
+ if (!arg->field.field) {
+ do_warning("%s: field %s not found",
+ __func__, arg->field.name);
+ return;
+ }
+ }
+ if (arg->field.field->size < 16) {
+ trace_seq_printf(s, "INVALID UUID: size have %u expect 16",
+ arg->field.field->size);
+ return;
+ }
+ buf = data + arg->field.field->offset;
+ /* first segment, %02x *4 */
+ for (i = 0; i < 4; i++, buf++)
+ trace_seq_printf(s, "%02x", *buf);
+
+ /* 2nd, 3rd, 4th segment, each segment is "-%02x%02x" */
+ for (i = 0; i < 3; i++, buf += 2)
+ trace_seq_printf(s, "-%02x%02x", buf[i * 2], buf[i * 2 + 1]);
+
+ /* Final segment, '-' and '%02x' *6 */
+ trace_seq_putc(s, '-');
+ for (i = 0; i < 6; i++, buf++)
+ trace_seq_printf(s, "%02x", *buf);
+}
+
static void print_mac_arg(struct trace_seq *s, int mac, void *data, int size,
struct tep_event *event, struct tep_print_arg *arg)
{
@@ -5074,6 +5114,22 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct tep_e
arg = arg->next;
break;
}
+ } else if (*ptr == 'U') {
+ /*
+ * %pU has several finetunings variants
+ * like %pUb and %pUL.
+ * Here we ignore them, default to
+ * byte-order no endian, lower case
+ * letters.
+ */
+ if (isalpha(ptr[1]))
+ ptr += 2;
+ else
+ ptr++;
+
+ print_uuid_arg(s, data, size, event, arg);
+ arg = arg->next;
+ break;
}
/* fall through */
--
2.23.0
On Thu, Oct 17, 2019 at 10:28:00AM +0800, Qu Wenruo wrote:
> [BUG]
> For btrfs related events, there is a field for fsid, but perf never
> parse it correctly.
>
> # perf trace -e btrfs:qgroup_meta_convert xfs_io -f -c "pwrite 0 4k" \
> /mnt/btrfs/file1
> 0.000 xfs_io/77915 btrfs:qgroup_meta_reserve:(nil)U: refroot=5(FS_TREE) type=0x0 diff=2
> ^^^^^^ Not a correct UUID
> ...
>
> [CAUSE]
> The pretty_print() function doesn't handle the %pU format correctly.
> In fact it doesn't handle %pU as uuid at all.
>
> [FIX]
> Add a new function, print_uuid_arg(), to handle %pU correctly.
>
> Now perf trace can at least print fsid correctly:
> 0.000 xfs_io/79619 btrfs:qgroup_meta_reserve:23ad1511-dd83-47d4-a79c-e96625a15a6e refroot=5(FS_TREE) type=0x0 diff=2
>
> Signed-off-by: Qu Wenruo <[email protected]>
> ---
> Changelog:
> v2:
> - Use more comment explaining the finetunings we skipped for %pU*
> - Use more elegant way to output uuid string
> ---
> tools/lib/traceevent/event-parse.c | 56 ++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
> index d948475585ce..3c9473f46efe 100644
> --- a/tools/lib/traceevent/event-parse.c
> +++ b/tools/lib/traceevent/event-parse.c
> @@ -18,6 +18,7 @@
> #include <errno.h>
> #include <stdint.h>
> #include <limits.h>
> +#include <linux/uuid.h>
> #include <linux/time64.h>
>
> #include <netinet/in.h>
> @@ -4508,6 +4509,45 @@ get_bprint_format(void *data, int size __maybe_unused,
> return format;
> }
>
> +static void print_uuid_arg(struct trace_seq *s, void *data, int size,
> + struct tep_event *event, struct tep_print_arg *arg)
> +{
> + unsigned char *buf;
> + int i;
> +
> + if (arg->type != TEP_PRINT_FIELD) {
> + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type);
> + return;
> + }
> +
> + if (!arg->field.field) {
> + arg->field.field = tep_find_any_field(event, arg->field.name);
> + if (!arg->field.field) {
> + do_warning("%s: field %s not found",
> + __func__, arg->field.name);
> + return;
> + }
> + }
> + if (arg->field.field->size < 16) {
> + trace_seq_printf(s, "INVALID UUID: size have %u expect 16",
> + arg->field.field->size);
> + return;
> + }
So if there's an interest for very compact printing loop, something like
this produces the same output:
for (i = 0; i < 8; i++) {
printf("%02X", buf[i]);
printf("%02X", buf[i]);
if (1 <= i && i <= 4)
putchar('-');
}
"23ad 1511 - dd83 - 47d4 - a79c - e966 25a1 5a6e"
0 1 2 3 4 5 6 7
IOW, split into pairs and print dash after a few of them.
On Thu, Oct 17, 2019 at 01:52:09PM +0200, David Sterba wrote:
> On Thu, Oct 17, 2019 at 10:28:00AM +0800, Qu Wenruo wrote:
> > [BUG]
> > For btrfs related events, there is a field for fsid, but perf never
> > parse it correctly.
> >
> > # perf trace -e btrfs:qgroup_meta_convert xfs_io -f -c "pwrite 0 4k" \
> > /mnt/btrfs/file1
> > 0.000 xfs_io/77915 btrfs:qgroup_meta_reserve:(nil)U: refroot=5(FS_TREE) type=0x0 diff=2
> > ^^^^^^ Not a correct UUID
> > ...
> >
> > [CAUSE]
> > The pretty_print() function doesn't handle the %pU format correctly.
> > In fact it doesn't handle %pU as uuid at all.
> >
> > [FIX]
> > Add a new function, print_uuid_arg(), to handle %pU correctly.
> >
> > Now perf trace can at least print fsid correctly:
> > 0.000 xfs_io/79619 btrfs:qgroup_meta_reserve:23ad1511-dd83-47d4-a79c-e96625a15a6e refroot=5(FS_TREE) type=0x0 diff=2
> >
> > Signed-off-by: Qu Wenruo <[email protected]>
> > ---
> > Changelog:
> > v2:
> > - Use more comment explaining the finetunings we skipped for %pU*
> > - Use more elegant way to output uuid string
> > ---
> > tools/lib/traceevent/event-parse.c | 56 ++++++++++++++++++++++++++++++
> > 1 file changed, 56 insertions(+)
> >
> > diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
> > index d948475585ce..3c9473f46efe 100644
> > --- a/tools/lib/traceevent/event-parse.c
> > +++ b/tools/lib/traceevent/event-parse.c
> > @@ -18,6 +18,7 @@
> > #include <errno.h>
> > #include <stdint.h>
> > #include <limits.h>
> > +#include <linux/uuid.h>
> > #include <linux/time64.h>
> >
> > #include <netinet/in.h>
> > @@ -4508,6 +4509,45 @@ get_bprint_format(void *data, int size __maybe_unused,
> > return format;
> > }
> >
> > +static void print_uuid_arg(struct trace_seq *s, void *data, int size,
> > + struct tep_event *event, struct tep_print_arg *arg)
> > +{
> > + unsigned char *buf;
> > + int i;
> > +
> > + if (arg->type != TEP_PRINT_FIELD) {
> > + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type);
> > + return;
> > + }
> > +
> > + if (!arg->field.field) {
> > + arg->field.field = tep_find_any_field(event, arg->field.name);
> > + if (!arg->field.field) {
> > + do_warning("%s: field %s not found",
> > + __func__, arg->field.name);
> > + return;
> > + }
> > + }
> > + if (arg->field.field->size < 16) {
> > + trace_seq_printf(s, "INVALID UUID: size have %u expect 16",
> > + arg->field.field->size);
> > + return;
> > + }
>
> So if there's an interest for very compact printing loop, something like
> this produces the same output:
>
> for (i = 0; i < 8; i++) {
> printf("%02X", buf[i]);
> printf("%02X", buf[i]);
Ok, test-before-post failure, this should be
printf("%02X", buf[2 * i]);
printf("%02X", buf[2 * i + 1]);
> if (1 <= i && i <= 4)
> putchar('-');
> }
On Thu, 17 Oct 2019 13:54:23 +0200
David Sterba <[email protected]> wrote:
> > So if there's an interest for very compact printing loop, something like
> > this produces the same output:
> >
> > for (i = 0; i < 8; i++) {
> > printf("%02X", buf[i]);
> > printf("%02X", buf[i]);
>
> Ok, test-before-post failure, this should be
>
> printf("%02X", buf[2 * i]);
> printf("%02X", buf[2 * i + 1]);
>
> > if (1 <= i && i <= 4)
> > putchar('-');
> > }
I'm fine if you want to post a v3 with this update.
-- Steve