perf: header: Regression

perf: header: Regression

[Andrew Jones]

The patch series that contains 7e94cfcc9d20 regresses the
header output. Below is a diff of info from before and
after the series

58,64c58,59
< # node1 meminfo  : total = 16777216 kB, free = 15712440 kB
< # node1 cpu list : 2,6,10,14,18,22,26,30
< # node2 meminfo  : total = 16777216 kB, free = 16299132 kB
< # node2 cpu list : 1,5,9,13,17,21,25,29
< # node3 meminfo  : total = 16777216 kB, free = 16217192 kB
< # node3 cpu list : 3,7,11,15,19,23,27,31
< # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19,
uncore_mbox_1 = 20, uncore_rbox_0 = 21, uncore_rbox_1 = 22, uncore_sbox_0
= 17, uncore_sbox_1 = 18, breakpoint = 5, uncore_ubox = 6, uncore_wbox =
23
---
> # numa topology : not available
> # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19# pmu
mappings: unable to read

As can be seen in the diff, before the series we had complete
numa info and pmu mappings info. After we get 

"# numa topology : not available" and "# pmu
mappings: unable to read"

Drew

Re: perf: header: Regression

[Namhyung Kim]

Hi Andrew,

On Mon, 22 Oct 2012 15:11:42 +0200, Andrew Jones wrote:
> The patch series that contains 7e94cfcc9d20 regresses the
> header output. Below is a diff of info from before and
> after the series
>
> 58,64c58,59
> < # node1 meminfo  : total = 16777216 kB, free = 15712440 kB
> < # node1 cpu list : 2,6,10,14,18,22,26,30
> < # node2 meminfo  : total = 16777216 kB, free = 16299132 kB
> < # node2 cpu list : 1,5,9,13,17,21,25,29
> < # node3 meminfo  : total = 16777216 kB, free = 16217192 kB
> < # node3 cpu list : 3,7,11,15,19,23,27,31
> < # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
> 15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
> uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
> 12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19,
> uncore_mbox_1 = 20, uncore_rbox_0 = 21, uncore_rbox_1 = 22, uncore_sbox_0
> = 17, uncore_sbox_1 = 18, breakpoint = 5, uncore_ubox = 6, uncore_wbox =
> 23
> ---
>> # numa topology : not available
>> # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
> 15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
> uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
> 12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19# pmu
> mappings: unable to read
>
> As can be seen in the diff, before the series we had complete
> numa info and pmu mappings info. After we get 
>
> "# numa topology : not available" and "# pmu
> mappings: unable to read"

Hmm.. I couldn't reproduce on my system:

# node0 meminfo  : total = 33505624 kB, free = 25213528 kB
# node0 cpu list : 0-11
# pmu mappings: cpu = 4, software = 1, uncore_pcu = 13, tracepoint = 2,
uncore_imc_0 = 15, uncore_imc_1 = 16, uncore_imc_2 = 17, uncore_imc_3
= 18, uncore_qpi_0 = 19, u = 20, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, un = 12,
uncore_ha = 14, uncore_r2pcie = 21, uncore_r3qpi_0 = 22,
uncore_r3qpi_1 = 23, breakpoint = 5, uncore_ubox = 6 

I don't have a NUMA machine.  Could you send your perf.data file or a
link via private mail?

Thanks,
Namhyung

Re: perf: header: Regression

[Andrew Jones]

On Tue, Oct 23, 2012 at 11:07:07AM +0900, Namhyung Kim wrote:
> Hi Andrew,
> 
> On Mon, 22 Oct 2012 15:11:42 +0200, Andrew Jones wrote:
> > The patch series that contains 7e94cfcc9d20 regresses the
> > header output. Below is a diff of info from before and
> > after the series
> >
> > 58,64c58,59
> > < # node1 meminfo  : total = 16777216 kB, free = 15712440 kB
> > < # node1 cpu list : 2,6,10,14,18,22,26,30
> > < # node2 meminfo  : total = 16777216 kB, free = 16299132 kB
> > < # node2 cpu list : 1,5,9,13,17,21,25,29
> > < # node3 meminfo  : total = 16777216 kB, free = 16217192 kB
> > < # node3 cpu list : 3,7,11,15,19,23,27,31
> > < # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
> > 15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
> > uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
> > 12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19,
> > uncore_mbox_1 = 20, uncore_rbox_0 = 21, uncore_rbox_1 = 22, uncore_sbox_0
> > = 17, uncore_sbox_1 = 18, breakpoint = 5, uncore_ubox = 6, uncore_wbox =
> > 23
> > ---
> >> # numa topology : not available
> >> # pmu mappings: cpu = 4, software = 1, tracepoint = 2, uncore_bbox_0 =
> > 15, uncore_bbox_1 = 16, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
> > uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, uncore_cbox_5 =
> > 12, uncore_cbox_6 = 13, uncore_cbox_7 = 14, uncore_mbox_0 = 19# pmu
> > mappings: unable to read
> >
> > As can be seen in the diff, before the series we had complete
> > numa info and pmu mappings info. After we get 
> >
> > "# numa topology : not available" and "# pmu
> > mappings: unable to read"
> 
> Hmm.. I couldn't reproduce on my system:
> 
> # node0 meminfo  : total = 33505624 kB, free = 25213528 kB
> # node0 cpu list : 0-11
> # pmu mappings: cpu = 4, software = 1, uncore_pcu = 13, tracepoint = 2,
> uncore_imc_0 = 15, uncore_imc_1 = 16, uncore_imc_2 = 17, uncore_imc_3
> = 18, uncore_qpi_0 = 19, u = 20, uncore_cbox_0 = 7, uncore_cbox_1 = 8,
> uncore_cbox_2 = 9, uncore_cbox_3 = 10, uncore_cbox_4 = 11, un = 12,
> uncore_ha = 14, uncore_r2pcie = 21, uncore_r3qpi_0 = 22,
> uncore_r3qpi_1 = 23, breakpoint = 5, uncore_ubox = 6 
> 
> I don't have a NUMA machine.  Could you send your perf.data file or a
> link via private mail?

I sent a link to my perf.data in a private mail. Let me know if you'd like
me to test a fix.

Thanks,
drew

> 
> Thanks,
> Namhyung

[PATCH 1/2] perf header: Fix numa topology printing

[Namhyung Kim]

Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
processed session env when printing") regresses the header output.
It was because of a missed string pointer calculation in the loop.

Reported-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/header.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 7daad237dea5..566b84c695c8 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1378,6 +1378,8 @@ static void print_numa_topology(struct perf_header *ph, int fd __maybe_unused,
 
 		str = tmp + 1;
 		fprintf(fp, "# node%u cpu list : %s\n", c, str);
+
+		str += strlen(str) + 1;
 	}
 	return;
 error:
-- 
1.7.9.2

[PATCH 2/2] perf tools: Fix strbuf_addf() when the buffer needs to grow

[Namhyung Kim]

This was found during chasing down the header output regression.
The strbuf_addf() was checking buffer length with a result of
vscnprintf() which cannot be greater than that of strbuf_avail().

Since numa topology and pmu mapping info in header were converted
to use strbuf, it sometimes caused uninteresting behaviors with the
broken strbuf.

Fix it by using vsnprintf() which returns desired output string
length regardless of the available buffer size and grow the buffer
if needed.

Reported-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/strbuf.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
index 2eeb51baf077..cfa906882e2c 100644
--- a/tools/perf/util/strbuf.c
+++ b/tools/perf/util/strbuf.c
@@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 	if (!strbuf_avail(sb))
 		strbuf_grow(sb, 64);
 	va_start(ap, fmt);
-	len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 	va_end(ap);
 	if (len < 0)
-		die("your vscnprintf is broken");
+		die("your vsnprintf is broken");
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
 		va_start(ap, fmt);
-		len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 		va_end(ap);
 		if (len > strbuf_avail(sb)) {
-			die("this should not happen, your snprintf is broken");
+			die("this should not happen, your vsnprintf is broken");
 		}
 	}
 	strbuf_setlen(sb, sb->len + len);
-- 
1.7.9.2

Re: [PATCH 2/2] perf tools: Fix strbuf_addf() when the buffer needs to grow

[Andrew Jones]

On Tue, Oct 23, 2012 at 10:44:50PM +0900, Namhyung Kim wrote:
> This was found during chasing down the header output regression.
> The strbuf_addf() was checking buffer length with a result of
> vscnprintf() which cannot be greater than that of strbuf_avail().
> 
> Since numa topology and pmu mapping info in header were converted
> to use strbuf, it sometimes caused uninteresting behaviors with the
> broken strbuf.
> 
> Fix it by using vsnprintf() which returns desired output string
> length regardless of the available buffer size and grow the buffer
> if needed.
> 
> Reported-by: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/util/strbuf.c |    8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
> index 2eeb51baf077..cfa906882e2c 100644
> --- a/tools/perf/util/strbuf.c
> +++ b/tools/perf/util/strbuf.c
> @@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
>  	if (!strbuf_avail(sb))
>  		strbuf_grow(sb, 64);
>  	va_start(ap, fmt);
> -	len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> +	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
>  	va_end(ap);
>  	if (len < 0)
> -		die("your vscnprintf is broken");
> +		die("your vsnprintf is broken");
>  	if (len > strbuf_avail(sb)) {
>  		strbuf_grow(sb, len);
>  		va_start(ap, fmt);
> -		len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> +		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
>  		va_end(ap);
>  		if (len > strbuf_avail(sb)) {
> -			die("this should not happen, your snprintf is broken");
> +			die("this should not happen, your vsnprintf is broken");
>  		}
>  	}
>  	strbuf_setlen(sb, sb->len + len);
> -- 
> 1.7.9.2
>

Tested-by: Andrew Jones <drjones@redhat.com> 

[tip:perf/urgent] perf tools: Fix strbuf_addf() when the buffer needs to grow

[tip-bot for Namhyung Kim]

Commit-ID:  f787d9519fb10411f2948f5b9957a1669879ba84
Gitweb:     http://git.kernel.org/tip/f787d9519fb10411f2948f5b9957a1669879ba84
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Tue, 23 Oct 2012 22:44:50 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 30 Oct 2012 10:32:56 -0200

perf tools: Fix strbuf_addf() when the buffer needs to grow

This was found during chasing down the header output regression.  The
strbuf_addf() was checking buffer length with a result of vscnprintf()
which cannot be greater than that of strbuf_avail().

Since numa topology and pmu mapping info in header were converted to use
strbuf, it sometimes caused uninteresting behaviors with the broken
strbuf.

Fix it by using vsnprintf() which returns desired output string length
regardless of the available buffer size and grow the buffer if needed.

Reported-by: Andrew Jones <drjones@redhat.com>
Tested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1350999890-6920-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/strbuf.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
index 2eeb51b..cfa9068 100644
--- a/tools/perf/util/strbuf.c
+++ b/tools/perf/util/strbuf.c
@@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 	if (!strbuf_avail(sb))
 		strbuf_grow(sb, 64);
 	va_start(ap, fmt);
-	len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 	va_end(ap);
 	if (len < 0)
-		die("your vscnprintf is broken");
+		die("your vsnprintf is broken");
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
 		va_start(ap, fmt);
-		len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 		va_end(ap);
 		if (len > strbuf_avail(sb)) {
-			die("this should not happen, your snprintf is broken");
+			die("this should not happen, your vsnprintf is broken");
 		}
 	}
 	strbuf_setlen(sb, sb->len + len);

Re: [PATCH 1/2] perf header: Fix numa topology printing

[Andrew Jones]

On Tue, Oct 23, 2012 at 10:44:49PM +0900, Namhyung Kim wrote:
> Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
> processed session env when printing") regresses the header output.
> It was because of a missed string pointer calculation in the loop.
> 
> Reported-by: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/util/header.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 7daad237dea5..566b84c695c8 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1378,6 +1378,8 @@ static void print_numa_topology(struct perf_header *ph, int fd __maybe_unused,
>  
>  		str = tmp + 1;
>  		fprintf(fp, "# node%u cpu list : %s\n", c, str);
> +
> +		str += strlen(str) + 1;
>  	}
>  	return;
>  error:
> -- 
> 1.7.9.2
>

works for me

Tested-by: Andrew Jones <drjones@redhat.com> 

Re: [PATCH 1/2] perf header: Fix numa topology printing

[Namhyung Kim]

Hi Andrew,

On Tue, 23 Oct 2012 16:12:19 +0200, Andrew Jones wrote:
> On Tue, Oct 23, 2012 at 10:44:49PM +0900, Namhyung Kim wrote:
>> Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
>> processed session env when printing") regresses the header output.
>> It was because of a missed string pointer calculation in the loop.
>
> works for me
>
> Tested-by: Andrew Jones <drjones@redhat.com> 

Did you test both of the patches?

Thanks,
Namhyung

Re: [PATCH 1/2] perf header: Fix numa topology printing

[Andrew Jones]

On Wed, Oct 24, 2012 at 04:00:08PM +0900, Namhyung Kim wrote:
> Hi Andrew,
> 
> On Tue, 23 Oct 2012 16:12:19 +0200, Andrew Jones wrote:
> > On Tue, Oct 23, 2012 at 10:44:49PM +0900, Namhyung Kim wrote:
> >> Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
> >> processed session env when printing") regresses the header output.
> >> It was because of a missed string pointer calculation in the loop.
> >
> > works for me
> >
> > Tested-by: Andrew Jones <drjones@redhat.com> 
> 
> Did you test both of the patches?

Yes, I applied both before testing. I'll add a tested by to the other
as well.

drew

> 
> Thanks,
> Namhyung

Re: [PATCH 1/2] perf header: Fix numa topology printing

[Namhyung Kim]

2012-10-24 (수), 09:49 +0200, Andrew Jones:
> On Wed, Oct 24, 2012 at 04:00:08PM +0900, Namhyung Kim wrote:
> > On Tue, 23 Oct 2012 16:12:19 +0200, Andrew Jones wrote:
> > > On Tue, Oct 23, 2012 at 10:44:49PM +0900, Namhyung Kim wrote:
> > >> Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
> > >> processed session env when printing") regresses the header output.
> > >> It was because of a missed string pointer calculation in the loop.
> > >
> > > works for me
> > >
> > > Tested-by: Andrew Jones <drjones@redhat.com> 
> > 
> > Did you test both of the patches?
> 
> Yes, I applied both before testing. I'll add a tested by to the other
> as well.

Arnaldo, I think these two should go through the urgent branch.  Would
you apply them?

Thanks,
Namhyung

[tip:perf/urgent] perf header: Fix numa topology printing

[tip-bot for Namhyung Kim]

Commit-ID:  1234471e2d11e4ee47f6de452dd8b8aeb09b45de
Gitweb:     http://git.kernel.org/tip/1234471e2d11e4ee47f6de452dd8b8aeb09b45de
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Tue, 23 Oct 2012 22:44:49 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 30 Oct 2012 10:32:55 -0200

perf header: Fix numa topology printing

Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
processed session env when printing") regresses the header output.  It
was because of a missed string pointer calculation in the loop.

Reported-by: Andrew Jones <drjones@redhat.com>
Tested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1350999890-6920-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/header.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 7daad23..566b84c 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1378,6 +1378,8 @@ static void print_numa_topology(struct perf_header *ph, int fd __maybe_unused,
 
 		str = tmp + 1;
 		fprintf(fp, "# node%u cpu list : %s\n", c, str);
+
+		str += strlen(str) + 1;
 	}
 	return;
 error:

[GIT PULL 0/2] perf/urgent fixes

[Arnaldo Carvalho de Melo]

Hi Ingo,

	Please consider pulling,

- Arnaldo

The following changes since commit 0d855354ea351bec6b222e9fea86a876cfafdcb6:

  perf, powerpc: Fix hw breakpoints returning -ENOSPC (2012-10-30 10:07:58 +0100)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux tags/perf-urgent-for-mingo

for you to fetch changes up to f787d9519fb10411f2948f5b9957a1669879ba84:

  perf tools: Fix strbuf_addf() when the buffer needs to grow (2012-10-30 10:32:56 -0200)

----------------------------------------------------------------
perf/urgent fixes

.  Fix numa topology printing, from Namhyung Kim.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

----------------------------------------------------------------
Namhyung Kim (2):
      perf header: Fix numa topology printing
      perf tools: Fix strbuf_addf() when the buffer needs to grow

 tools/perf/util/header.c |    2 ++
 tools/perf/util/strbuf.c |    8 ++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

[PATCH 1/2] perf header: Fix numa topology printing

[Arnaldo Carvalho de Melo]

From: Namhyung Kim <namhyung@kernel.org>

Andrew reported that the commit 7e94cfcc9d20 ("perf header: Use pre-
processed session env when printing") regresses the header output.  It
was because of a missed string pointer calculation in the loop.

Reported-by: Andrew Jones <drjones@redhat.com>
Tested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1350999890-6920-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/header.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 7daad23..566b84c 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1378,6 +1378,8 @@ static void print_numa_topology(struct perf_header *ph, int fd __maybe_unused,
 
 		str = tmp + 1;
 		fprintf(fp, "# node%u cpu list : %s\n", c, str);
+
+		str += strlen(str) + 1;
 	}
 	return;
 error:
-- 
1.7.9.2.358.g22243