* [PATCH 1/3] perf expr: Add debug logging for literals
@ 2021-11-23 22:48 Ian Rogers
2021-11-23 22:48 ` [PATCH 2/3] perf tools: Fix SMT not detected with large core count Ian Rogers
2021-11-23 22:48 ` [PATCH 3/3] perf tools: Probe non-deprecated sysfs path 1st Ian Rogers
0 siblings, 2 replies; 5+ messages in thread
From: Ian Rogers @ 2021-11-23 22:48 UTC (permalink / raw)
To: Andi Kleen, Jiri Olsa, Namhyung Kim, John Garry, Kajol Jain,
Paul A . Clarke, Arnaldo Carvalho de Melo, Kan Liang,
Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Konstantin Khlebnikov, linux-perf-users, linux-kernel
Cc: eranian, Ian Rogers
Useful for diagnosing problems with metrics.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/expr.c | 35 ++++++++++++++++++++++++-----------
1 file changed, 24 insertions(+), 11 deletions(-)
diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
index 1d532b9fed29..cdbab4f959fe 100644
--- a/tools/perf/util/expr.c
+++ b/tools/perf/util/expr.c
@@ -395,12 +395,17 @@ double expr_id_data__source_count(const struct expr_id_data *data)
double expr__get_literal(const char *literal)
{
static struct cpu_topology *topology;
+ double result = NAN;
- if (!strcmp("#smt_on", literal))
- return smt_on() > 0 ? 1.0 : 0.0;
+ if (!strcmp("#smt_on", literal)) {
+ result = smt_on() > 0 ? 1.0 : 0.0;
+ goto out;
+ }
- if (!strcmp("#num_cpus", literal))
- return cpu__max_present_cpu();
+ if (!strcmp("#num_cpus", literal)) {
+ result = cpu__max_present_cpu();
+ goto out;
+ }
/*
* Assume that topology strings are consistent, such as CPUs "0-1"
@@ -415,13 +420,21 @@ double expr__get_literal(const char *literal)
return NAN;
}
}
- if (!strcmp("#num_packages", literal))
- return topology->package_cpus_lists;
- if (!strcmp("#num_dies", literal))
- return topology->die_cpus_lists;
- if (!strcmp("#num_cores", literal))
- return topology->core_cpus_lists;
+ if (!strcmp("#num_packages", literal)) {
+ result = topology->package_cpus_lists;
+ goto out;
+ }
+ if (!strcmp("#num_dies", literal)) {
+ result = topology->die_cpus_lists;
+ goto out;
+ }
+ if (!strcmp("#num_cores", literal)) {
+ result = topology->core_cpus_lists;
+ goto out;
+ }
pr_err("Unrecognized literal '%s'", literal);
- return NAN;
+out:
+ pr_debug2("literal: %s = %f\n", literal, result);
+ return result;
}
--
2.34.0.rc2.393.gf8c9666880-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/3] perf tools: Fix SMT not detected with large core count
2021-11-23 22:48 [PATCH 1/3] perf expr: Add debug logging for literals Ian Rogers
@ 2021-11-23 22:48 ` Ian Rogers
2021-11-23 23:34 ` Arnaldo Carvalho de Melo
2021-11-23 22:48 ` [PATCH 3/3] perf tools: Probe non-deprecated sysfs path 1st Ian Rogers
1 sibling, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2021-11-23 22:48 UTC (permalink / raw)
To: Andi Kleen, Jiri Olsa, Namhyung Kim, John Garry, Kajol Jain,
Paul A . Clarke, Arnaldo Carvalho de Melo, Kan Liang,
Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Konstantin Khlebnikov, linux-perf-users, linux-kernel
Cc: eranian, Ian Rogers
sysfs__read_int returns 0 on success, and so the fast read path was
always failing.
strtoull can only read a 64-bit bitmap. On an AMD EPYC core_cpus may look
like:
00000000,00000000,00000000,00000001,00000000,00000000,00000000,00000001
and so the sibling wasn't spotted. Fix by writing a simple hweight string
parser.
Fixes: bb629484d924 (perf tools: Simplify checking if SMT is active.)
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/smt.c | 68 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 58 insertions(+), 10 deletions(-)
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c
index 20bacd5972ad..2636be65305a 100644
--- a/tools/perf/util/smt.c
+++ b/tools/perf/util/smt.c
@@ -5,6 +5,56 @@
#include "api/fs/fs.h"
#include "smt.h"
+/**
+ * hweight_str - Returns the number of bits set in str. Stops at first non-hex
+ * or ',' character.
+ */
+static int hweight_str(char *str)
+{
+ int result = 0;
+
+ while (*str) {
+ switch (*str++) {
+ case '0':
+ case ',':
+ break;
+ case '1':
+ case '2':
+ case '4':
+ case '8':
+ result++;
+ break;
+ case '3':
+ case '5':
+ case '6':
+ case '9':
+ case 'a':
+ case 'A':
+ case 'c':
+ case 'C':
+ result += 2;
+ break;
+ case '7':
+ case 'b':
+ case 'B':
+ case 'd':
+ case 'D':
+ case 'e':
+ case 'E':
+ result += 3;
+ break;
+ case 'f':
+ case 'F':
+ result += 4;
+ break;
+ default:
+ goto done;
+ }
+ }
+done:
+ return result;
+}
+
int smt_on(void)
{
static bool cached;
@@ -15,9 +65,12 @@ int smt_on(void)
if (cached)
return cached_result;
- if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0)
- goto done;
+ if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) {
+ cached = true;
+ return cached_result;
+ }
+ cached_result = 0;
ncpu = sysconf(_SC_NPROCESSORS_CONF);
for (cpu = 0; cpu < ncpu; cpu++) {
unsigned long long siblings;
@@ -35,18 +88,13 @@ int smt_on(void)
continue;
}
/* Entry is hex, but does not have 0x, so need custom parser */
- siblings = strtoull(str, NULL, 16);
+ siblings = hweight_str(str);
free(str);
- if (hweight64(siblings) > 1) {
+ if (siblings > 1) {
cached_result = 1;
- cached = true;
break;
}
}
- if (!cached) {
- cached_result = 0;
-done:
- cached = true;
- }
+ cached = true;
return cached_result;
}
--
2.34.0.rc2.393.gf8c9666880-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 3/3] perf tools: Probe non-deprecated sysfs path 1st
2021-11-23 22:48 [PATCH 1/3] perf expr: Add debug logging for literals Ian Rogers
2021-11-23 22:48 ` [PATCH 2/3] perf tools: Fix SMT not detected with large core count Ian Rogers
@ 2021-11-23 22:48 ` Ian Rogers
1 sibling, 0 replies; 5+ messages in thread
From: Ian Rogers @ 2021-11-23 22:48 UTC (permalink / raw)
To: Andi Kleen, Jiri Olsa, Namhyung Kim, John Garry, Kajol Jain,
Paul A . Clarke, Arnaldo Carvalho de Melo, Kan Liang,
Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Konstantin Khlebnikov, linux-perf-users, linux-kernel
Cc: eranian, Ian Rogers
Following Documentation/ABI/stable/sysfs-devices-system-cpu the
/sys/devices/system/cpu/cpuX/topology/core_cpus is deprecated in favor
of thread_siblings, so probe thread_siblings before falling back on
core_cpus.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/smt.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c
index 2636be65305a..2b0a36ebf27a 100644
--- a/tools/perf/util/smt.c
+++ b/tools/perf/util/smt.c
@@ -79,11 +79,10 @@ int smt_on(void)
char fn[256];
snprintf(fn, sizeof fn,
- "devices/system/cpu/cpu%d/topology/core_cpus", cpu);
+ "devices/system/cpu/cpu%d/topology/thread_siblings", cpu);
if (sysfs__read_str(fn, &str, &strlen) < 0) {
snprintf(fn, sizeof fn,
- "devices/system/cpu/cpu%d/topology/thread_siblings",
- cpu);
+ "devices/system/cpu/cpu%d/topology/core_cpus", cpu);
if (sysfs__read_str(fn, &str, &strlen) < 0)
continue;
}
--
2.34.0.rc2.393.gf8c9666880-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] perf tools: Fix SMT not detected with large core count
2021-11-23 22:48 ` [PATCH 2/3] perf tools: Fix SMT not detected with large core count Ian Rogers
@ 2021-11-23 23:34 ` Arnaldo Carvalho de Melo
2021-11-24 0:02 ` Ian Rogers
0 siblings, 1 reply; 5+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-11-23 23:34 UTC (permalink / raw)
To: Ian Rogers
Cc: Andi Kleen, Jiri Olsa, Namhyung Kim, John Garry, Kajol Jain,
Paul A . Clarke, Kan Liang, Peter Zijlstra, Ingo Molnar,
Mark Rutland, Alexander Shishkin, Konstantin Khlebnikov,
linux-perf-users, linux-kernel, eranian
Em Tue, Nov 23, 2021 at 02:48:20PM -0800, Ian Rogers escreveu:
> sysfs__read_int returns 0 on success, and so the fast read path was
> always failing.
Please split this into two patches, the above part should be in one, and
the strtoull in another.
Also can't we just do as ./tools/perf/util/cputopo.c and use instead
core_cpus_list?
On a 5950x:
⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu31/topology/core_cpus
80008000
⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu31/topology/core_cpus_list
15,31
⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu0/topology/core_cpus
00010001
⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu0/topology/core_cpus_list
0,16
⬢[acme@toolbox perf]$
- Arnaldo
> strtoull can only read a 64-bit bitmap. On an AMD EPYC core_cpus may look
> like:
> 00000000,00000000,00000000,00000001,00000000,00000000,00000000,00000001
> and so the sibling wasn't spotted. Fix by writing a simple hweight string
> parser.
>
> Fixes: bb629484d924 (perf tools: Simplify checking if SMT is active.)
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/smt.c | 68 ++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 58 insertions(+), 10 deletions(-)
>
> diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c
> index 20bacd5972ad..2636be65305a 100644
> --- a/tools/perf/util/smt.c
> +++ b/tools/perf/util/smt.c
> @@ -5,6 +5,56 @@
> #include "api/fs/fs.h"
> #include "smt.h"
>
> +/**
> + * hweight_str - Returns the number of bits set in str. Stops at first non-hex
> + * or ',' character.
> + */
> +static int hweight_str(char *str)
> +{
> + int result = 0;
> +
> + while (*str) {
> + switch (*str++) {
> + case '0':
> + case ',':
> + break;
> + case '1':
> + case '2':
> + case '4':
> + case '8':
> + result++;
> + break;
> + case '3':
> + case '5':
> + case '6':
> + case '9':
> + case 'a':
> + case 'A':
> + case 'c':
> + case 'C':
> + result += 2;
> + break;
> + case '7':
> + case 'b':
> + case 'B':
> + case 'd':
> + case 'D':
> + case 'e':
> + case 'E':
> + result += 3;
> + break;
> + case 'f':
> + case 'F':
> + result += 4;
> + break;
> + default:
> + goto done;
> + }
> + }
> +done:
> + return result;
> +}
> +
> int smt_on(void)
> {
> static bool cached;
> @@ -15,9 +65,12 @@ int smt_on(void)
> if (cached)
> return cached_result;
>
> - if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0)
> - goto done;
> + if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) {
> + cached = true;
> + return cached_result;
> + }
>
> + cached_result = 0;
> ncpu = sysconf(_SC_NPROCESSORS_CONF);
> for (cpu = 0; cpu < ncpu; cpu++) {
> unsigned long long siblings;
> @@ -35,18 +88,13 @@ int smt_on(void)
> continue;
> }
> /* Entry is hex, but does not have 0x, so need custom parser */
> - siblings = strtoull(str, NULL, 16);
> + siblings = hweight_str(str);
> free(str);
> - if (hweight64(siblings) > 1) {
> + if (siblings > 1) {
> cached_result = 1;
> - cached = true;
> break;
> }
> }
> - if (!cached) {
> - cached_result = 0;
> -done:
> - cached = true;
> - }
> + cached = true;
> return cached_result;
> }
> --
> 2.34.0.rc2.393.gf8c9666880-goog
--
- Arnaldo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] perf tools: Fix SMT not detected with large core count
2021-11-23 23:34 ` Arnaldo Carvalho de Melo
@ 2021-11-24 0:02 ` Ian Rogers
0 siblings, 0 replies; 5+ messages in thread
From: Ian Rogers @ 2021-11-24 0:02 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Andi Kleen, Jiri Olsa, Namhyung Kim, John Garry, Kajol Jain,
Paul A . Clarke, Kan Liang, Peter Zijlstra, Ingo Molnar,
Mark Rutland, Alexander Shishkin, Konstantin Khlebnikov,
linux-perf-users, linux-kernel, eranian
On Tue, Nov 23, 2021 at 3:34 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Tue, Nov 23, 2021 at 02:48:20PM -0800, Ian Rogers escreveu:
> > sysfs__read_int returns 0 on success, and so the fast read path was
> > always failing.
>
> Please split this into two patches, the above part should be in one, and
> the strtoull in another.
Will do.
> Also can't we just do as ./tools/perf/util/cputopo.c and use instead
> core_cpus_list?
It is more complex for the list case as the list may have a range. It
shouldn't really matter with the active fix in any case. I think
ideally we'd have an abstraction like cpuset in util-linux:
https://github.com/util-linux/util-linux/blob/master/lib/cpuset.c
This is a bit beyond what I'm trying to fix here.
Thanks,
Ian
> On a 5950x:
>
> ⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu31/topology/core_cpus
> 80008000
> ⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu31/topology/core_cpus_list
> 15,31
> ⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu0/topology/core_cpus
> 00010001
> ⬢[acme@toolbox perf]$ cat /sys/devices/system/cpu/cpu0/topology/core_cpus_list
> 0,16
> ⬢[acme@toolbox perf]$
>
> - Arnaldo
>
> > strtoull can only read a 64-bit bitmap. On an AMD EPYC core_cpus may look
> > like:
> > 00000000,00000000,00000000,00000001,00000000,00000000,00000000,00000001
> > and so the sibling wasn't spotted. Fix by writing a simple hweight string
> > parser.
> >
> > Fixes: bb629484d924 (perf tools: Simplify checking if SMT is active.)
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> > tools/perf/util/smt.c | 68 ++++++++++++++++++++++++++++++++++++-------
> > 1 file changed, 58 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c
> > index 20bacd5972ad..2636be65305a 100644
> > --- a/tools/perf/util/smt.c
> > +++ b/tools/perf/util/smt.c
> > @@ -5,6 +5,56 @@
> > #include "api/fs/fs.h"
> > #include "smt.h"
> >
> > +/**
> > + * hweight_str - Returns the number of bits set in str. Stops at first non-hex
> > + * or ',' character.
> > + */
> > +static int hweight_str(char *str)
> > +{
> > + int result = 0;
> > +
> > + while (*str) {
> > + switch (*str++) {
> > + case '0':
> > + case ',':
> > + break;
> > + case '1':
> > + case '2':
> > + case '4':
> > + case '8':
> > + result++;
> > + break;
> > + case '3':
> > + case '5':
> > + case '6':
> > + case '9':
> > + case 'a':
> > + case 'A':
> > + case 'c':
> > + case 'C':
> > + result += 2;
> > + break;
> > + case '7':
> > + case 'b':
> > + case 'B':
> > + case 'd':
> > + case 'D':
> > + case 'e':
> > + case 'E':
> > + result += 3;
> > + break;
> > + case 'f':
> > + case 'F':
> > + result += 4;
> > + break;
> > + default:
> > + goto done;
> > + }
> > + }
> > +done:
> > + return result;
> > +}
> > +
> > int smt_on(void)
> > {
> > static bool cached;
> > @@ -15,9 +65,12 @@ int smt_on(void)
> > if (cached)
> > return cached_result;
> >
> > - if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0)
> > - goto done;
> > + if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) {
> > + cached = true;
> > + return cached_result;
> > + }
> >
> > + cached_result = 0;
> > ncpu = sysconf(_SC_NPROCESSORS_CONF);
> > for (cpu = 0; cpu < ncpu; cpu++) {
> > unsigned long long siblings;
> > @@ -35,18 +88,13 @@ int smt_on(void)
> > continue;
> > }
> > /* Entry is hex, but does not have 0x, so need custom parser */
> > - siblings = strtoull(str, NULL, 16);
> > + siblings = hweight_str(str);
> > free(str);
> > - if (hweight64(siblings) > 1) {
> > + if (siblings > 1) {
> > cached_result = 1;
> > - cached = true;
> > break;
> > }
> > }
> > - if (!cached) {
> > - cached_result = 0;
> > -done:
> > - cached = true;
> > - }
> > + cached = true;
> > return cached_result;
> > }
> > --
> > 2.34.0.rc2.393.gf8c9666880-goog
>
> --
>
> - Arnaldo
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-11-24 0:03 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2021-11-23 22:48 [PATCH 1/3] perf expr: Add debug logging for literals Ian Rogers
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2021-11-23 23:34 ` Arnaldo Carvalho de Melo
2021-11-24 0:02 ` Ian Rogers
2021-11-23 22:48 ` [PATCH 3/3] perf tools: Probe non-deprecated sysfs path 1st Ian Rogers
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