2011-03-24 07:43:28

by Lin Ming

[permalink] [raw]
Subject: [PATCH] perf probe: Add fastpath to do lookup by function name

The vmlinux file may have thousands of CUs.
We can lookup function name from .debug_pubnames section
to avoid the slow loop on CUs.

Signed-off-by: Lin Ming <[email protected]>
---
tools/perf/util/probe-finder.c | 38 ++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-finder.h | 1 +
2 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 194f9e2..b2034c2 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1876,6 +1876,30 @@ static int find_line_range_by_func(struct line_finder *lf)
return param.retval;
}

+static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
+{
+ struct line_finder *lf = data;
+ struct line_range *lr = lf->lr;
+
+ if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
+ if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
+ return DWARF_CB_OK;
+
+ if (die_compare_name(&lf->sp_die, lr->function)) {
+ if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
+ return DWARF_CB_OK;
+
+ if (lr->file && !cu_find_realpath(&lf->cu_die, lr->file))
+ return DWARF_CB_OK;
+
+ lf->found = 1;
+ return DWARF_CB_ABORT;
+ }
+ }
+
+ return DWARF_CB_OK;
+}
+
int find_line_range(int fd, struct line_range *lr)
{
struct line_finder lf = {.lr = lr, .found = 0};
@@ -1895,6 +1919,19 @@ int find_line_range(int fd, struct line_range *lr)
return -EBADF;
}

+ /* Fastpath: lookup by function name from .debug_pubnames section */
+ if (lr->function) {
+ struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0};
+
+ dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0);
+ if (lf.found) {
+ lf.found = 0;
+ line_range_search_cb(&lf.sp_die, &param);
+ if (lf.found)
+ goto found;
+ }
+ }
+
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
@@ -1923,6 +1960,7 @@ int find_line_range(int fd, struct line_range *lr)
off = noff;
}

+found:
/* Store comp_dir */
if (lf.found) {
comp_dir = cu_get_comp_dir(&lf.cu_die);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index beaefc3..4bc56a4 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -83,6 +83,7 @@ struct line_finder {
int lno_s; /* Start line number */
int lno_e; /* End line number */
Dwarf_Die cu_die; /* Current CU */
+ Dwarf_Die sp_die;
int found;
};

--
1.7.2.3


2011-03-24 07:58:46

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name


* Lin Ming <[email protected]> wrote:

> The vmlinux file may have thousands of CUs.
> We can lookup function name from .debug_pubnames section
> to avoid the slow loop on CUs.

Mind including before/after perf stat --repeat 10 results in the changelog, of
an affected command which got faster?

Thanks,

Ingo

2011-03-24 08:39:05

by Lin Ming

[permalink] [raw]
Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name

On Thu, 2011-03-24 at 15:58 +0800, Ingo Molnar wrote:
> * Lin Ming <[email protected]> wrote:
>
> > The vmlinux file may have thousands of CUs.
> > We can lookup function name from .debug_pubnames section
> > to avoid the slow loop on CUs.
>
> Mind including before/after perf stat --repeat 10 results in the changelog, of
> an affected command which got faster?


>From 611a823a34e655d47a80f92994b004391e2b244c Mon Sep 17 00:00:00 2001
From: Lin Ming <[email protected]>
Date: Thu, 24 Mar 2011 23:22:24 +0800
Subject: [PATCH] perf probe: Add fastpath to do lookup by function name

The vmlinux file may have thousands of CUs.
We can lookup function name from .debug_pubnames section
to avoid the slow loop on CUs.

./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
-s /home/mlin/linux-2.6 \
--line csum_partial_copy_to_user > tmp.log

before patch applied
=====================
364.535892 task-clock-msecs # 0.997 CPUs
0 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
29,993 page-faults # 0.082 M/sec
865,862,109 cycles # 2375.245 M/sec
1,255,259,630 instructions # 1.450 IPC
252,400,884 branches # 692.390 M/sec
3,429,376 branch-misses # 1.359 %
1,386,990 cache-references # 3.805 M/sec
687,188 cache-misses # 1.885 M/sec

0.365792170 seconds time elapsed


after patch applied
=====================
89.896405 task-clock-msecs # 0.991 CPUs
1 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
10,145 page-faults # 0.113 M/sec
214,553,875 cycles # 2386.679 M/sec
226,915,559 instructions # 1.058 IPC
44,536,614 branches # 495.422 M/sec
613,074 branch-misses # 1.377 %
860,787 cache-references # 9.575 M/sec
442,380 cache-misses # 4.921 M/sec

0.090716032 seconds time elapsed


Signed-off-by: Lin Ming <[email protected]>
---
tools/perf/util/probe-finder.c | 38 ++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-finder.h | 1 +
2 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 194f9e2..b2034c2 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1876,6 +1876,30 @@ static int find_line_range_by_func(struct line_finder *lf)
return param.retval;
}

+static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
+{
+ struct line_finder *lf = data;
+ struct line_range *lr = lf->lr;
+
+ if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
+ if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
+ return DWARF_CB_OK;
+
+ if (die_compare_name(&lf->sp_die, lr->function)) {
+ if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
+ return DWARF_CB_OK;
+
+ if (lr->file && !cu_find_realpath(&lf->cu_die, lr->file))
+ return DWARF_CB_OK;
+
+ lf->found = 1;
+ return DWARF_CB_ABORT;
+ }
+ }
+
+ return DWARF_CB_OK;
+}
+
int find_line_range(int fd, struct line_range *lr)
{
struct line_finder lf = {.lr = lr, .found = 0};
@@ -1895,6 +1919,19 @@ int find_line_range(int fd, struct line_range *lr)
return -EBADF;
}

+ /* Fastpath: lookup by function name from .debug_pubnames section */
+ if (lr->function) {
+ struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0};
+
+ dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0);
+ if (lf.found) {
+ lf.found = 0;
+ line_range_search_cb(&lf.sp_die, &param);
+ if (lf.found)
+ goto found;
+ }
+ }
+
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
@@ -1923,6 +1960,7 @@ int find_line_range(int fd, struct line_range *lr)
off = noff;
}

+found:
/* Store comp_dir */
if (lf.found) {
comp_dir = cu_get_comp_dir(&lf.cu_die);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index beaefc3..4bc56a4 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -83,6 +83,7 @@ struct line_finder {
int lno_s; /* Start line number */
int lno_e; /* End line number */
Dwarf_Die cu_die; /* Current CU */
+ Dwarf_Die sp_die;
int found;
};

--
1.7.2.3


2011-03-24 08:47:32

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name


* Lin Ming <[email protected]> wrote:

> ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
> -s /home/mlin/linux-2.6 \
> --line csum_partial_copy_to_user > tmp.log
>
> before patch applied
> =====================
> 364.535892 task-clock-msecs # 0.997 CPUs
> 865,862,109 cycles # 2375.245 M/sec
> 1,255,259,630 instructions # 1.450 IPC

> after patch applied
> =====================
> 89.896405 task-clock-msecs # 0.991 CPUs
> 214,553,875 cycles # 2386.679 M/sec
> 226,915,559 instructions # 1.058 IPC

That's a very nice speedup :-)

Thanks,

Ingo

Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name

(2011/03/25 0:38), Lin Ming wrote:
> The vmlinux file may have thousands of CUs.
> We can lookup function name from .debug_pubnames section
> to avoid the slow loop on CUs.
>
> Signed-off-by: Lin Ming <[email protected]>
> ---
> tools/perf/util/probe-finder.c | 38 ++++++++++++++++++++++++++++++++++++++
> tools/perf/util/probe-finder.h | 1 +
> 2 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 194f9e2..b2034c2 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1876,6 +1876,30 @@ static int find_line_range_by_func(struct line_finder *lf)
> return param.retval;
> }
>
> +static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
> +{
> + struct line_finder *lf = data;
> + struct line_range *lr = lf->lr;
> +
> + if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
> + if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
> + return DWARF_CB_OK;
> +
> + if (die_compare_name(&lf->sp_die, lr->function)) {
> + if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
> + return DWARF_CB_OK;
> +

Just one comment.
Could you ensure that the decl_file of sp_die matches lr->file (by strtailcmp) here?

Other parts look good to me:)

Thanks!

> + if (lr->file && !cu_find_realpath(&lf->cu_die, lr->file))
> + return DWARF_CB_OK;
> +
> + lf->found = 1;
> + return DWARF_CB_ABORT;
> + }
> + }
> +
> + return DWARF_CB_OK;
> +}
> +
> int find_line_range(int fd, struct line_range *lr)
> {
> struct line_finder lf = {.lr = lr, .found = 0};
> @@ -1895,6 +1919,19 @@ int find_line_range(int fd, struct line_range *lr)
> return -EBADF;
> }
>
> + /* Fastpath: lookup by function name from .debug_pubnames section */
> + if (lr->function) {
> + struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0};
> +
> + dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0);
> + if (lf.found) {
> + lf.found = 0;
> + line_range_search_cb(&lf.sp_die, &param);
> + if (lf.found)
> + goto found;
> + }
> + }
> +
> /* Loop on CUs (Compilation Unit) */
> while (!lf.found && ret >= 0) {
> if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
> @@ -1923,6 +1960,7 @@ int find_line_range(int fd, struct line_range *lr)
> off = noff;
> }
>
> +found:
> /* Store comp_dir */
> if (lf.found) {
> comp_dir = cu_get_comp_dir(&lf.cu_die);
> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
> index beaefc3..4bc56a4 100644
> --- a/tools/perf/util/probe-finder.h
> +++ b/tools/perf/util/probe-finder.h
> @@ -83,6 +83,7 @@ struct line_finder {
> int lno_s; /* Start line number */
> int lno_e; /* End line number */
> Dwarf_Die cu_die; /* Current CU */
> + Dwarf_Die sp_die;
> int found;
> };
>


--
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: [email protected]

2011-03-24 13:47:30

by Lin Ming

[permalink] [raw]
Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name

On Thu, 2011-03-24 at 17:08 +0800, Masami Hiramatsu wrote:
> (2011/03/25 0:38), Lin Ming wrote:
> > The vmlinux file may have thousands of CUs.
> > We can lookup function name from .debug_pubnames section
> > to avoid the slow loop on CUs.
> >
> > Signed-off-by: Lin Ming <[email protected]>
> > ---
> > tools/perf/util/probe-finder.c | 38 ++++++++++++++++++++++++++++++++++++++
> > tools/perf/util/probe-finder.h | 1 +
> > 2 files changed, 39 insertions(+), 0 deletions(-)
> >
> > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> > index 194f9e2..b2034c2 100644
> > --- a/tools/perf/util/probe-finder.c
> > +++ b/tools/perf/util/probe-finder.c
> > @@ -1876,6 +1876,30 @@ static int find_line_range_by_func(struct line_finder *lf)
> > return param.retval;
> > }
> >
> > +static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
> > +{
> > + struct line_finder *lf = data;
> > + struct line_range *lr = lf->lr;
> > +
> > + if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
> > + if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
> > + return DWARF_CB_OK;
> > +
> > + if (die_compare_name(&lf->sp_die, lr->function)) {
> > + if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
> > + return DWARF_CB_OK;
> > +
>
> Just one comment.
> Could you ensure that the decl_file of sp_die matches lr->file (by strtailcmp) here?

OK, so the file name compare with cu_find_realpath(..) can be removed,
as below.

This makes the lookup a bit more faster again.

Thanks, I'll post a new version with below changes.

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b2034c2..38e4a05 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1880,6 +1880,7 @@ static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
{
struct line_finder *lf = data;
struct line_range *lr = lf->lr;
+ const char *file;

if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
@@ -1889,8 +1890,12 @@ static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
return DWARF_CB_OK;

- if (lr->file && !cu_find_realpath(&lf->cu_die, lr->file))
- return DWARF_CB_OK;
+ if (lr->file) {
+ file = dwarf_decl_file(&lf->sp_die);
+
+ if (file && strtailcmp(file, lr->file))
+ return DWARF_CB_OK;
+ }

lf->found = 1;
return DWARF_CB_ABORT;



2011-03-24 14:09:14

by Lin Ming

[permalink] [raw]
Subject: [PATCH v2 -tip] perf probe: Add fastpath to do lookup by function name

v2 -> v1:
- Don't compare file names with cu_find_realpath(...), instead, compare them
with the name returned by dwarf_decl_file(sp_die)

The vmlinux file may have thousands of CUs.
We can lookup function name from .debug_pubnames section
to avoid the slow loop on CUs.

./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
-s /home/mlin/linux-2.6 \
--line csum_partial_copy_to_user > tmp.log

before patch applied
=====================
364.535892 task-clock-msecs # 0.997 CPUs
0 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
29,993 page-faults # 0.082 M/sec
865,862,109 cycles # 2375.245 M/sec
1,255,259,630 instructions # 1.450 IPC
252,400,884 branches # 692.390 M/sec
3,429,376 branch-misses # 1.359 %
1,386,990 cache-references # 3.805 M/sec
687,188 cache-misses # 1.885 M/sec

0.365792170 seconds time elapsed

after patch applied
=====================
89.896405 task-clock-msecs # 0.991 CPUs
1 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
10,145 page-faults # 0.113 M/sec
214,553,875 cycles # 2386.679 M/sec
226,915,559 instructions # 1.058 IPC
44,536,614 branches # 495.422 M/sec
613,074 branch-misses # 1.377 %
860,787 cache-references # 9.575 M/sec
442,380 cache-misses # 4.921 M/sec

0.090716032 seconds time elapsed

Signed-off-by: Lin Ming <[email protected]>
---
tools/perf/util/probe-finder.c | 39 +++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-finder.h | 1 +
2 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 194f9e2..5cf044c 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1876,6 +1876,31 @@ static int find_line_range_by_func(struct line_finder *lf)
return param.retval;
}

+static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
+{
+ struct line_finder *lf = data;
+ struct line_range *lr = lf->lr;
+
+ if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
+ if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
+ return DWARF_CB_OK;
+
+ if (die_compare_name(&lf->sp_die, lr->function)) {
+ if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
+ return DWARF_CB_OK;
+
+ if (lr->file &&
+ strtailcmp(lr->file, dwarf_decl_file(&lf->sp_die)))
+ return DWARF_CB_OK;
+
+ lf->found = 1;
+ return DWARF_CB_ABORT;
+ }
+ }
+
+ return DWARF_CB_OK;
+}
+
int find_line_range(int fd, struct line_range *lr)
{
struct line_finder lf = {.lr = lr, .found = 0};
@@ -1895,6 +1920,19 @@ int find_line_range(int fd, struct line_range *lr)
return -EBADF;
}

+ /* Fastpath: lookup by function name from .debug_pubnames section */
+ if (lr->function) {
+ struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0};
+
+ dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0);
+ if (lf.found) {
+ lf.found = 0;
+ line_range_search_cb(&lf.sp_die, &param);
+ if (lf.found)
+ goto found;
+ }
+ }
+
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
@@ -1923,6 +1961,7 @@ int find_line_range(int fd, struct line_range *lr)
off = noff;
}

+found:
/* Store comp_dir */
if (lf.found) {
comp_dir = cu_get_comp_dir(&lf.cu_die);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index beaefc3..4bc56a4 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -83,6 +83,7 @@ struct line_finder {
int lno_s; /* Start line number */
int lno_e; /* End line number */
Dwarf_Die cu_die; /* Current CU */
+ Dwarf_Die sp_die;
int found;
};

--
1.7.2.3


Subject: Re: [PATCH v2 -tip] perf probe: Add fastpath to do lookup by function name

(2011/03/24 23:09), Lin Ming wrote:
> v2 -> v1:
> - Don't compare file names with cu_find_realpath(...), instead, compare them
> with the name returned by dwarf_decl_file(sp_die)
>
> The vmlinux file may have thousands of CUs.
> We can lookup function name from .debug_pubnames section
> to avoid the slow loop on CUs.
>
> ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
> -s /home/mlin/linux-2.6 \
> --line csum_partial_copy_to_user > tmp.log
>
> before patch applied
> =====================
> 364.535892 task-clock-msecs # 0.997 CPUs
> 0 context-switches # 0.000 M/sec
> 0 CPU-migrations # 0.000 M/sec
> 29,993 page-faults # 0.082 M/sec
> 865,862,109 cycles # 2375.245 M/sec
> 1,255,259,630 instructions # 1.450 IPC
> 252,400,884 branches # 692.390 M/sec
> 3,429,376 branch-misses # 1.359 %
> 1,386,990 cache-references # 3.805 M/sec
> 687,188 cache-misses # 1.885 M/sec
>
> 0.365792170 seconds time elapsed
>
> after patch applied
> =====================
> 89.896405 task-clock-msecs # 0.991 CPUs
> 1 context-switches # 0.000 M/sec
> 0 CPU-migrations # 0.000 M/sec
> 10,145 page-faults # 0.113 M/sec
> 214,553,875 cycles # 2386.679 M/sec
> 226,915,559 instructions # 1.058 IPC
> 44,536,614 branches # 495.422 M/sec
> 613,074 branch-misses # 1.377 %
> 860,787 cache-references # 9.575 M/sec
> 442,380 cache-misses # 4.921 M/sec
>
> 0.090716032 seconds time elapsed

Thanks! Looks very good :)

Acked-by: Masami Hiramatsu <[email protected]>

>
> Signed-off-by: Lin Ming <[email protected]>
> ---
> tools/perf/util/probe-finder.c | 39 +++++++++++++++++++++++++++++++++++++++
> tools/perf/util/probe-finder.h | 1 +
> 2 files changed, 40 insertions(+), 0 deletions(-)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 194f9e2..5cf044c 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1876,6 +1876,31 @@ static int find_line_range_by_func(struct line_finder *lf)
> return param.retval;
> }
>
> +static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
> +{
> + struct line_finder *lf = data;
> + struct line_range *lr = lf->lr;
> +
> + if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) {
> + if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram)
> + return DWARF_CB_OK;
> +
> + if (die_compare_name(&lf->sp_die, lr->function)) {
> + if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die))
> + return DWARF_CB_OK;
> +
> + if (lr->file &&
> + strtailcmp(lr->file, dwarf_decl_file(&lf->sp_die)))
> + return DWARF_CB_OK;
> +
> + lf->found = 1;
> + return DWARF_CB_ABORT;
> + }
> + }
> +
> + return DWARF_CB_OK;
> +}
> +
> int find_line_range(int fd, struct line_range *lr)
> {
> struct line_finder lf = {.lr = lr, .found = 0};
> @@ -1895,6 +1920,19 @@ int find_line_range(int fd, struct line_range *lr)
> return -EBADF;
> }
>
> + /* Fastpath: lookup by function name from .debug_pubnames section */
> + if (lr->function) {
> + struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0};
> +
> + dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0);
> + if (lf.found) {
> + lf.found = 0;
> + line_range_search_cb(&lf.sp_die, &param);
> + if (lf.found)
> + goto found;
> + }
> + }
> +
> /* Loop on CUs (Compilation Unit) */
> while (!lf.found && ret >= 0) {
> if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
> @@ -1923,6 +1961,7 @@ int find_line_range(int fd, struct line_range *lr)
> off = noff;
> }
>
> +found:
> /* Store comp_dir */
> if (lf.found) {
> comp_dir = cu_get_comp_dir(&lf.cu_die);
> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
> index beaefc3..4bc56a4 100644
> --- a/tools/perf/util/probe-finder.h
> +++ b/tools/perf/util/probe-finder.h
> @@ -83,6 +83,7 @@ struct line_finder {
> int lno_s; /* Start line number */
> int lno_e; /* End line number */
> Dwarf_Die cu_die; /* Current CU */
> + Dwarf_Die sp_die;
> int found;
> };
>


--
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: [email protected]

2011-03-25 02:58:10

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v2 -tip] perf probe: Add fastpath to do lookup by function name

Em Fri, Mar 25, 2011 at 10:14:25AM +0900, Masami Hiramatsu escreveu:
> (2011/03/24 23:09), Lin Ming wrote:
> > v2 -> v1:
> > - Don't compare file names with cu_find_realpath(...), instead, compare them
> > with the name returned by dwarf_decl_file(sp_die)
> >
> > The vmlinux file may have thousands of CUs.
> > We can lookup function name from .debug_pubnames section
> > to avoid the slow loop on CUs.
> >
> > ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
> > -s /home/mlin/linux-2.6 \
> > --line csum_partial_copy_to_user > tmp.log
> >
> > before patch applied
> > =====================
> > 364.535892 task-clock-msecs # 0.997 CPUs
> > 0 context-switches # 0.000 M/sec
> > 0 CPU-migrations # 0.000 M/sec
> > 29,993 page-faults # 0.082 M/sec
> > 865,862,109 cycles # 2375.245 M/sec
> > 1,255,259,630 instructions # 1.450 IPC
> > 252,400,884 branches # 692.390 M/sec
> > 3,429,376 branch-misses # 1.359 %
> > 1,386,990 cache-references # 3.805 M/sec
> > 687,188 cache-misses # 1.885 M/sec
> >
> > 0.365792170 seconds time elapsed
> >
> > after patch applied
> > =====================
> > 89.896405 task-clock-msecs # 0.991 CPUs
> > 1 context-switches # 0.000 M/sec
> > 0 CPU-migrations # 0.000 M/sec
> > 10,145 page-faults # 0.113 M/sec
> > 214,553,875 cycles # 2386.679 M/sec
> > 226,915,559 instructions # 1.058 IPC
> > 44,536,614 branches # 495.422 M/sec
> > 613,074 branch-misses # 1.377 %
> > 860,787 cache-references # 9.575 M/sec
> > 442,380 cache-misses # 4.921 M/sec
> >
> > 0.090716032 seconds time elapsed
>
> Thanks! Looks very good :)
>
> Acked-by: Masami Hiramatsu <[email protected]>

Indeed, I'll try and process this one tomorrow,

Thanks a lot!

- Arnaldo

2011-03-25 06:34:12

by Lin Ming

[permalink] [raw]
Subject: Re: [PATCH v2 -tip] perf probe: Add fastpath to do lookup by function name

在 2011-03-25五的 10:57 +0800,Arnaldo Carvalho de Melo写道:
> Em Fri, Mar 25, 2011 at 10:14:25AM +0900, Masami Hiramatsu escreveu:
> > (2011/03/24 23:09), Lin Ming wrote:
> > > v2 -> v1:
> > > - Don't compare file names with cu_find_realpath(...), instead, compare them
> > > with the name returned by dwarf_decl_file(sp_die)
> > >
> > > The vmlinux file may have thousands of CUs.
> > > We can lookup function name from .debug_pubnames section
> > > to avoid the slow loop on CUs.
> > >
> > > ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
> > > -s /home/mlin/linux-2.6 \
> > > --line csum_partial_copy_to_user > tmp.log
> > >
> > > before patch applied
> > > =====================
> > > 364.535892 task-clock-msecs # 0.997 CPUs
> > > 0 context-switches # 0.000 M/sec
> > > 0 CPU-migrations # 0.000 M/sec
> > > 29,993 page-faults # 0.082 M/sec
> > > 865,862,109 cycles # 2375.245 M/sec
> > > 1,255,259,630 instructions # 1.450 IPC
> > > 252,400,884 branches # 692.390 M/sec
> > > 3,429,376 branch-misses # 1.359 %
> > > 1,386,990 cache-references # 3.805 M/sec
> > > 687,188 cache-misses # 1.885 M/sec
> > >
> > > 0.365792170 seconds time elapsed
> > >
> > > after patch applied
> > > =====================
> > > 89.896405 task-clock-msecs # 0.991 CPUs
> > > 1 context-switches # 0.000 M/sec
> > > 0 CPU-migrations # 0.000 M/sec
> > > 10,145 page-faults # 0.113 M/sec
> > > 214,553,875 cycles # 2386.679 M/sec
> > > 226,915,559 instructions # 1.058 IPC
> > > 44,536,614 branches # 495.422 M/sec
> > > 613,074 branch-misses # 1.377 %
> > > 860,787 cache-references # 9.575 M/sec
> > > 442,380 cache-misses # 4.921 M/sec
> > >
> > > 0.090716032 seconds time elapsed
> >
> > Thanks! Looks very good :)
> >
> > Acked-by: Masami Hiramatsu <[email protected]>
>
> Indeed, I'll try and process this one tomorrow,

Except find_line_range, I just realized that the same optimization maybe
added for find_probes.

Thanks,
Lin Ming

>
> Thanks a lot!
>
> - Arnaldo

2011-03-25 08:30:44

by Lin Ming

[permalink] [raw]
Subject: Re: [PATCH v2 -tip] perf probe: Add fastpath to do lookup by function name

On Fri, 2011-03-25 at 14:33 +0800, Lin Ming wrote:
> 在 2011-03-25五的 10:57 +0800,Arnaldo Carvalho de Melo写道:
> > Em Fri, Mar 25, 2011 at 10:14:25AM +0900, Masami Hiramatsu escreveu:
> > > (2011/03/24 23:09), Lin Ming wrote:
> > > > v2 -> v1:
> > > > - Don't compare file names with cu_find_realpath(...), instead, compare them
> > > > with the name returned by dwarf_decl_file(sp_die)
> > > >
> > > > The vmlinux file may have thousands of CUs.
> > > > We can lookup function name from .debug_pubnames section
> > > > to avoid the slow loop on CUs.
> > > >
> > > > ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \
> > > > -s /home/mlin/linux-2.6 \
> > > > --line csum_partial_copy_to_user > tmp.log
> > > >
> > > > before patch applied
> > > > =====================
> > > > 364.535892 task-clock-msecs # 0.997 CPUs
> > > > 0 context-switches # 0.000 M/sec
> > > > 0 CPU-migrations # 0.000 M/sec
> > > > 29,993 page-faults # 0.082 M/sec
> > > > 865,862,109 cycles # 2375.245 M/sec
> > > > 1,255,259,630 instructions # 1.450 IPC
> > > > 252,400,884 branches # 692.390 M/sec
> > > > 3,429,376 branch-misses # 1.359 %
> > > > 1,386,990 cache-references # 3.805 M/sec
> > > > 687,188 cache-misses # 1.885 M/sec
> > > >
> > > > 0.365792170 seconds time elapsed
> > > >
> > > > after patch applied
> > > > =====================
> > > > 89.896405 task-clock-msecs # 0.991 CPUs
> > > > 1 context-switches # 0.000 M/sec
> > > > 0 CPU-migrations # 0.000 M/sec
> > > > 10,145 page-faults # 0.113 M/sec
> > > > 214,553,875 cycles # 2386.679 M/sec
> > > > 226,915,559 instructions # 1.058 IPC
> > > > 44,536,614 branches # 495.422 M/sec
> > > > 613,074 branch-misses # 1.377 %
> > > > 860,787 cache-references # 9.575 M/sec
> > > > 442,380 cache-misses # 4.921 M/sec
> > > >
> > > > 0.090716032 seconds time elapsed
> > >
> > > Thanks! Looks very good :)
> > >
> > > Acked-by: Masami Hiramatsu <[email protected]>
> >
> > Indeed, I'll try and process this one tomorrow,
>
> Except find_line_range, I just realized that the same optimization maybe
> added for find_probes.

I have send out a v3 patch to add fastpath for find_probes.

Thanks,
Lin Ming

>
> Thanks,
> Lin Ming
>
> >
> > Thanks a lot!
> >
> > - Arnaldo
>