[PATCH v2 1/2] perf test workload noploop: Name the noploop process

[PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Ian Rogers]

Name the noploop process "perf-noploop" so that tests can easily check
for its existence.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/workloads/noploop.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
index 940ea5910a84..8b954d466083 100644
--- a/tools/perf/tests/workloads/noploop.c
+++ b/tools/perf/tests/workloads/noploop.c
@@ -2,6 +2,8 @@
 #include <stdlib.h>
 #include <signal.h>
 #include <unistd.h>
+#include <linux/prctl.h>
+#include <sys/prctl.h>
 #include <linux/compiler.h>
 #include "../tests.h"
 
@@ -16,6 +18,7 @@ static int noploop(int argc, const char **argv)
 {
 	int sec = 1;
 
+	prctl(PR_SET_NAME, "perf-noploop");
 	if (argc > 0)
 		sec = atoi(argv[0]);
 
-- 
2.50.0.rc2.701.gf1e915cc24-goog

[PATCH v2 2/2] perf test: Add sched latency and script shell tests

[Ian Rogers]

Add shell tests covering the `perf sched latency` and `perf sched
script` commands. The test creates 2 noploop processes on the same
forced CPU, it then checks that the process appears in the `perf
sched` output.

Signed-off-by: Ian Rogers <irogers@google.com>
---
v2: Skip the test if not root due to permissions.
---
 tools/perf/tests/shell/sched.sh | 91 +++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100755 tools/perf/tests/shell/sched.sh

diff --git a/tools/perf/tests/shell/sched.sh b/tools/perf/tests/shell/sched.sh
new file mode 100755
index 000000000000..0a4fe3f414e1
--- /dev/null
+++ b/tools/perf/tests/shell/sched.sh
@@ -0,0 +1,91 @@
+#!/bin/bash
+# perf sched tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+if [ "$(id -u)" != 0 ]; then
+  echo "[Skip] No root permission"
+  exit 2
+fi
+
+err=0
+perfdata=$(mktemp /tmp/__perf_test_sched.perf.data.XXXXX)
+PID1=0
+PID2=0
+
+cleanup() {
+  rm -f "${perfdata}"
+  rm -f "${perfdata}".old
+
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
+  cleanup
+  exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
+start_noploops() {
+  # Start two noploop workloads on CPU0 to trigger scheduling.
+  taskset -c 0 perf test -w noploop 10 &
+  PID1=$!
+  taskset -c 0 perf test -w noploop 10 &
+  PID2=$!
+
+  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID1/status"
+  then
+    echo "Sched [Error taskset did not work for the 1st noploop ($PID1)]"
+    grep Cpus_allowed /proc/$PID1/status
+    err=1
+  fi
+
+  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID2/status"
+  then
+    echo "Sched [Error taskset did not work for the 2nd noploop ($PID2)]"
+    grep Cpus_allowed /proc/$PID2/status
+    err=1
+  fi
+}
+
+cleanup_noploops() {
+  kill "$PID1" "$PID2"
+}
+
+test_sched_latency() {
+  echo "Sched latency"
+
+  start_noploops
+
+  perf sched record --no-inherit -o "${perfdata}" sleep 1
+  if ! perf sched latency -i "${perfdata}" | grep -q perf-noploop
+  then
+    echo "Sched latency [Failed missing output]"
+    err=1
+  fi
+
+  cleanup_noploops
+}
+
+test_sched_script() {
+  echo "Sched script"
+
+  start_noploops
+
+  perf sched record --no-inherit -o "${perfdata}" sleep 1
+  if ! perf sched script -i "${perfdata}" | grep -q perf-noploop
+  then
+    echo "Sched script [Failed missing output]"
+    err=1
+  fi
+
+  cleanup_noploops
+}
+
+test_sched_latency
+test_sched_script
+
+cleanup
+exit $err
-- 
2.50.0.rc2.701.gf1e915cc24-goog

Re: [PATCH v2 2/2] perf test: Add sched latency and script shell tests

[James Clark]

On 19/06/2025 1:20 am, Ian Rogers wrote:
> Add shell tests covering the `perf sched latency` and `perf sched
> script` commands. The test creates 2 noploop processes on the same
> forced CPU, it then checks that the process appears in the `perf
> sched` output.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> v2: Skip the test if not root due to permissions.
> ---
>   tools/perf/tests/shell/sched.sh | 91 +++++++++++++++++++++++++++++++++
>   1 file changed, 91 insertions(+)
>   create mode 100755 tools/perf/tests/shell/sched.sh
> 
> diff --git a/tools/perf/tests/shell/sched.sh b/tools/perf/tests/shell/sched.sh
> new file mode 100755
> index 000000000000..0a4fe3f414e1
> --- /dev/null
> +++ b/tools/perf/tests/shell/sched.sh
> @@ -0,0 +1,91 @@
> +#!/bin/bash
> +# perf sched tests
> +# SPDX-License-Identifier: GPL-2.0
> +
> +set -e
> +
> +if [ "$(id -u)" != 0 ]; then
> +  echo "[Skip] No root permission"
> +  exit 2
> +fi
> +
> +err=0
> +perfdata=$(mktemp /tmp/__perf_test_sched.perf.data.XXXXX)
> +PID1=0
> +PID2=0
> +
> +cleanup() {
> +  rm -f "${perfdata}"
> +  rm -f "${perfdata}".old
> +
> +  trap - EXIT TERM INT
> +}
> +
> +trap_cleanup() {
> +  echo "Unexpected signal in ${FUNCNAME[1]}"
> +  cleanup
> +  exit 1
> +}
> +trap trap_cleanup EXIT TERM INT
> +
> +start_noploops() {
> +  # Start two noploop workloads on CPU0 to trigger scheduling.
> +  taskset -c 0 perf test -w noploop 10 &
> +  PID1=$!
> +  taskset -c 0 perf test -w noploop 10 &
> +  PID2=$!
> +
> +  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID1/status"

Hi Ian,

Because taskset is also run in the background it's possible to grep the 
proc file before it's managed to re-pin itself. I saw some intermittent 
failures of the test because of this.

I think you'd need to run noploop in the background but taskset in the 
foreground and give it the pid of noploop to make sure it finishes 
before grepping.

Other than that the test seems ok:

Reviewed-by: James Clark <james.clark@linaro.org>

Thanks
James

> +  then
> +    echo "Sched [Error taskset did not work for the 1st noploop ($PID1)]"
> +    grep Cpus_allowed /proc/$PID1/status
> +    err=1
> +  fi
> +
> +  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID2/status"
> +  then
> +    echo "Sched [Error taskset did not work for the 2nd noploop ($PID2)]"
> +    grep Cpus_allowed /proc/$PID2/status
> +    err=1
> +  fi
> +}
> +
> +cleanup_noploops() {
> +  kill "$PID1" "$PID2"
> +}
> +
> +test_sched_latency() {
> +  echo "Sched latency"
> +
> +  start_noploops
> +
> +  perf sched record --no-inherit -o "${perfdata}" sleep 1
> +  if ! perf sched latency -i "${perfdata}" | grep -q perf-noploop
> +  then
> +    echo "Sched latency [Failed missing output]"
> +    err=1
> +  fi
> +
> +  cleanup_noploops
> +}
> +
> +test_sched_script() {
> +  echo "Sched script"
> +
> +  start_noploops
> +
> +  perf sched record --no-inherit -o "${perfdata}" sleep 1
> +  if ! perf sched script -i "${perfdata}" | grep -q perf-noploop
> +  then
> +    echo "Sched script [Failed missing output]"
> +    err=1
> +  fi
> +
> +  cleanup_noploops
> +}
> +
> +test_sched_latency
> +test_sched_script
> +
> +cleanup
> +exit $err

Re: [PATCH v2 2/2] perf test: Add sched latency and script shell tests

[Namhyung Kim]

On Wed, Jun 18, 2025 at 05:20:34PM -0700, Ian Rogers wrote:
> Add shell tests covering the `perf sched latency` and `perf sched
> script` commands. The test creates 2 noploop processes on the same
> forced CPU, it then checks that the process appears in the `perf
> sched` output.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> v2: Skip the test if not root due to permissions.
> ---
>  tools/perf/tests/shell/sched.sh | 91 +++++++++++++++++++++++++++++++++
>  1 file changed, 91 insertions(+)
>  create mode 100755 tools/perf/tests/shell/sched.sh
> 
> diff --git a/tools/perf/tests/shell/sched.sh b/tools/perf/tests/shell/sched.sh
> new file mode 100755
> index 000000000000..0a4fe3f414e1
> --- /dev/null
> +++ b/tools/perf/tests/shell/sched.sh
> @@ -0,0 +1,91 @@
> +#!/bin/bash
> +# perf sched tests
> +# SPDX-License-Identifier: GPL-2.0
> +
> +set -e
> +
> +if [ "$(id -u)" != 0 ]; then
> +  echo "[Skip] No root permission"
> +  exit 2
> +fi
> +
> +err=0
> +perfdata=$(mktemp /tmp/__perf_test_sched.perf.data.XXXXX)
> +PID1=0
> +PID2=0
> +
> +cleanup() {
> +  rm -f "${perfdata}"
> +  rm -f "${perfdata}".old
> +
> +  trap - EXIT TERM INT
> +}
> +
> +trap_cleanup() {
> +  echo "Unexpected signal in ${FUNCNAME[1]}"
> +  cleanup
> +  exit 1
> +}
> +trap trap_cleanup EXIT TERM INT
> +
> +start_noploops() {
> +  # Start two noploop workloads on CPU0 to trigger scheduling.
> +  taskset -c 0 perf test -w noploop 10 &
> +  PID1=$!
> +  taskset -c 0 perf test -w noploop 10 &
> +  PID2=$!

You can use 'thloop' workload which runs 2 threads at the same time.
Then you don't need to handle the background processes and run it
directly with perf test.

Thanks,
Namhyung

> +
> +  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID1/status"
> +  then
> +    echo "Sched [Error taskset did not work for the 1st noploop ($PID1)]"
> +    grep Cpus_allowed /proc/$PID1/status
> +    err=1
> +  fi
> +
> +  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID2/status"
> +  then
> +    echo "Sched [Error taskset did not work for the 2nd noploop ($PID2)]"
> +    grep Cpus_allowed /proc/$PID2/status
> +    err=1
> +  fi
> +}
> +
> +cleanup_noploops() {
> +  kill "$PID1" "$PID2"
> +}
> +
> +test_sched_latency() {
> +  echo "Sched latency"
> +
> +  start_noploops
> +
> +  perf sched record --no-inherit -o "${perfdata}" sleep 1
> +  if ! perf sched latency -i "${perfdata}" | grep -q perf-noploop
> +  then
> +    echo "Sched latency [Failed missing output]"
> +    err=1
> +  fi
> +
> +  cleanup_noploops
> +}
> +
> +test_sched_script() {
> +  echo "Sched script"
> +
> +  start_noploops
> +
> +  perf sched record --no-inherit -o "${perfdata}" sleep 1
> +  if ! perf sched script -i "${perfdata}" | grep -q perf-noploop
> +  then
> +    echo "Sched script [Failed missing output]"
> +    err=1
> +  fi
> +
> +  cleanup_noploops
> +}
> +
> +test_sched_latency
> +test_sched_script
> +
> +cleanup
> +exit $err
> -- 
> 2.50.0.rc2.701.gf1e915cc24-goog
> 

Re: [PATCH v2 2/2] perf test: Add sched latency and script shell tests

[Ian Rogers]

On Fri, Jun 20, 2025 at 12:41 PM Namhyung Kim <namhyung@kernel.org> wrote:
> You can use 'thloop' workload which runs 2 threads at the same time.
> Then you don't need to handle the background processes and run it
> directly with perf test.

v3 sent. I held off changing noploop to thloop as I think 2 separate
processes is a little clearer:
https://lore.kernel.org/lkml/20250628012302.1242532-1-irogers@google.com/

Thanks,
Ian

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[James Clark]

On 19/06/2025 1:20 am, Ian Rogers wrote:
> Name the noploop process "perf-noploop" so that tests can easily check
> for its existence.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>   tools/perf/tests/workloads/noploop.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
> index 940ea5910a84..8b954d466083 100644
> --- a/tools/perf/tests/workloads/noploop.c
> +++ b/tools/perf/tests/workloads/noploop.c
> @@ -2,6 +2,8 @@
>   #include <stdlib.h>
>   #include <signal.h>
>   #include <unistd.h>
> +#include <linux/prctl.h>
> +#include <sys/prctl.h>
>   #include <linux/compiler.h>
>   #include "../tests.h"
>   
> @@ -16,6 +18,7 @@ static int noploop(int argc, const char **argv)
>   {
>   	int sec = 1;
>   
> +	prctl(PR_SET_NAME, "perf-noploop");
>   	if (argc > 0)
>   		sec = atoi(argv[0]);
>   

Reviewed-by: James Clark <james.clark@linaro.org>

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Namhyung Kim]

Hi Ian,

On Wed, Jun 18, 2025 at 05:20:33PM -0700, Ian Rogers wrote:
> Name the noploop process "perf-noploop" so that tests can easily check
> for its existence.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/tests/workloads/noploop.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
> index 940ea5910a84..8b954d466083 100644
> --- a/tools/perf/tests/workloads/noploop.c
> +++ b/tools/perf/tests/workloads/noploop.c
> @@ -2,6 +2,8 @@
>  #include <stdlib.h>
>  #include <signal.h>
>  #include <unistd.h>
> +#include <linux/prctl.h>
> +#include <sys/prctl.h>

I'm afraid it'd introduce a build failure on musl.  Please see

https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/

I think <sys/prctl.h> would be enough.

Thanks,
Namhyung


>  #include <linux/compiler.h>
>  #include "../tests.h"
>  
> @@ -16,6 +18,7 @@ static int noploop(int argc, const char **argv)
>  {
>  	int sec = 1;
>  
> +	prctl(PR_SET_NAME, "perf-noploop");
>  	if (argc > 0)
>  		sec = atoi(argv[0]);
>  
> -- 
> 2.50.0.rc2.701.gf1e915cc24-goog
> 

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Ian Rogers]

On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hi Ian,
>
> On Wed, Jun 18, 2025 at 05:20:33PM -0700, Ian Rogers wrote:
> > Name the noploop process "perf-noploop" so that tests can easily check
> > for its existence.
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> >  tools/perf/tests/workloads/noploop.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
> > index 940ea5910a84..8b954d466083 100644
> > --- a/tools/perf/tests/workloads/noploop.c
> > +++ b/tools/perf/tests/workloads/noploop.c
> > @@ -2,6 +2,8 @@
> >  #include <stdlib.h>
> >  #include <signal.h>
> >  #include <unistd.h>
> > +#include <linux/prctl.h>
> > +#include <sys/prctl.h>
>
> I'm afraid it'd introduce a build failure on musl.  Please see
>
> https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/
>
> I think <sys/prctl.h> would be enough.

Hi Namhyung,

we could do that but in the glibc man page it says:
https://man7.org/linux/man-pages/man2/prctl.2.html
```
#include <linux/prctl.h>  /* Definition of PR_* constants */
#include <sys/prctl.h>
```
So wouldn't the PR_SET_NAME definition potentially be missing then? We
could fill in the missing definition with `#ifndef PR_SET_NAME` it
seems sub-optimal - I see this is what was done in the linked to
changes. Perhaps we need something like a tools/perf/util/prctl.h, and
a feature test, then in that we have something like:
```
/* A header file to work around musl libc breakages caused conflicting
definitions in linux/prctl.h . */
#ifndef HAVE_SENSIBLE_PRCTL
#  include <linux/prctl.h>
#  include <sys/prctl.h>
#else // !HAVE_SENSIBLE_PRCTL
#  include <sys/prctl.h>
#  ifndef PR_SET_NAME
#    define PR_SET_NAME 15
#  endif // PR_SET_NAME
#  ifndef PR_FUTEX_HASH
#    define PR_FUTEX_HASH                   78
#    define PR_FUTEX_HASH_SET_SLOTS        1
#    define FH_FLAG_IMMUTABLE              (1ULL << 0)
#    define PR_FUTEX_HASH_GET_SLOTS        2
#    define PR_FUTEX_HASH_GET_IMMUTABLE    3
#  endif // PR_FUTEX_HASH
#endif // HAVE_SENSIBLE_PRCTL
```
The feature test would just be to include the two headers and see if
the build breaks.

It'd be nice to think musl was slowly getting fixed. I notice we're
carrying two comments in the code about working around musl, but I
suspect we do this kind of thing in a lot of places (just knowing the
issues that come up from yourself and Arnaldo when trying to integrate
patches). It'd be nice if perf's code could keep close to what the man
page, or whatever, is saying the standard should be, rather than doing
some kind of adhoc linux/prctl.h rewrite (or if we are doing that,
make the code more explicit that it's what we're doing).

It'd be nice to think that the perf code could be clean wrt analyses
like "include what you use" [1], but strategically removing #includes
to try to work around musl issues seems like the opposite of this.

Thanks,
Ian

[1] https://github.com/include-what-you-use/include-what-you-use

> Thanks,
> Namhyung
>
>
> >  #include <linux/compiler.h>
> >  #include "../tests.h"
> >
> > @@ -16,6 +18,7 @@ static int noploop(int argc, const char **argv)
> >  {
> >       int sec = 1;
> >
> > +     prctl(PR_SET_NAME, "perf-noploop");
> >       if (argc > 0)
> >               sec = atoi(argv[0]);
> >
> > --
> > 2.50.0.rc2.701.gf1e915cc24-goog
> >

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Arnaldo Carvalho de Melo]

On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > I'm afraid it'd introduce a build failure on musl.  Please see

> > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/

> > I think <sys/prctl.h> would be enough.
 
> we could do that but in the glibc man page it says:
> https://man7.org/linux/man-pages/man2/prctl.2.html
> ```
> #include <linux/prctl.h>  /* Definition of PR_* constants */
> #include <sys/prctl.h>
> ```

> It'd be nice to think musl was slowly getting fixed. I notice we're

Sebastian reported on the musl libc, its maintainer replied:

https://www.openwall.com/lists/musl/2025/06/12/11

- ARnaldo

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Ian Rogers]

On Mon, Jun 23, 2025 at 10:45 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> > On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > I'm afraid it'd introduce a build failure on musl.  Please see
>
> > > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/
>
> > > I think <sys/prctl.h> would be enough.
>
> > we could do that but in the glibc man page it says:
> > https://man7.org/linux/man-pages/man2/prctl.2.html
> > ```
> > #include <linux/prctl.h>  /* Definition of PR_* constants */
> > #include <sys/prctl.h>
> > ```
>
> > It'd be nice to think musl was slowly getting fixed. I notice we're
>
> Sebastian reported on the musl libc, its maintainer replied:
>
> https://www.openwall.com/lists/musl/2025/06/12/11

Ugh. I'm not sure how we're expected to resolve this and have glibc
and musl be happy without basically not trusting libc.

Thanks,
Ian

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Namhyung Kim]

On Mon, Jun 23, 2025 at 11:05:41AM -0700, Ian Rogers wrote:
> On Mon, Jun 23, 2025 at 10:45 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> > > On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > > I'm afraid it'd introduce a build failure on musl.  Please see
> >
> > > > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/
> >
> > > > I think <sys/prctl.h> would be enough.
> >
> > > we could do that but in the glibc man page it says:
> > > https://man7.org/linux/man-pages/man2/prctl.2.html
> > > ```
> > > #include <linux/prctl.h>  /* Definition of PR_* constants */
> > > #include <sys/prctl.h>
> > > ```
> >
> > > It'd be nice to think musl was slowly getting fixed. I notice we're
> >
> > Sebastian reported on the musl libc, its maintainer replied:
> >
> > https://www.openwall.com/lists/musl/2025/06/12/11
> 
> Ugh. I'm not sure how we're expected to resolve this and have glibc
> and musl be happy without basically not trusting libc.

Maybe pthread_setname_np()?  It seems musl also implemented it.

Thanks,
Namhyung

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Arnaldo Carvalho de Melo]

On Mon, Jun 23, 2025 at 11:14:47AM -0700, Namhyung Kim wrote:
> On Mon, Jun 23, 2025 at 11:05:41AM -0700, Ian Rogers wrote:
> > On Mon, Jun 23, 2025 at 10:45 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> > > On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> > > > On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > > > I'm afraid it'd introduce a build failure on musl.  Please see

> > > > > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/

> > > > > I think <sys/prctl.h> would be enough.

> > > > we could do that but in the glibc man page it says:
> > > > https://man7.org/linux/man-pages/man2/prctl.2.html
> > > > ```
> > > > #include <linux/prctl.h>  /* Definition of PR_* constants */
> > > > #include <sys/prctl.h>
> > > > ```

> > > > It'd be nice to think musl was slowly getting fixed. I notice we're

> > > Sebastian reported on the musl libc, its maintainer replied:

> > > https://www.openwall.com/lists/musl/2025/06/12/11

> > Ugh. I'm not sure how we're expected to resolve this and have glibc
> > and musl be happy without basically not trusting libc.

> Maybe pthread_setname_np()?  It seems musl also implemented it.

⬢ [acme@toolbx perf-tools-next]$ git diff
diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
index 8b954d4660833a2f..656e472e618822a3 100644
--- a/tools/perf/tests/workloads/noploop.c
+++ b/tools/perf/tests/workloads/noploop.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0 */
+#include <pthread.h>
 #include <stdlib.h>
 #include <signal.h>
 #include <unistd.h>
-#include <linux/prctl.h>
-#include <sys/prctl.h>
 #include <linux/compiler.h>
 #include "../tests.h"
 
@@ -18,7 +17,7 @@ static int noploop(int argc, const char **argv)
 {
        int sec = 1;
 
-       prctl(PR_SET_NAME, "perf-noploop");
+       pthread_setname_np(pthread_self(), "perf-noploop");
        if (argc > 0)
                sec = atoi(argv[0]);
 
⬢ [acme@toolbx perf-tools-next]$ 

⬢ [acme@toolbx perf-tools-next]$ perf test -w noploop &
[1] 1179763
⬢ [acme@toolbx perf-tools-next]$ ps
    PID TTY          TIME CMD
   3935 pts/1    00:00:00 bash
   4053 pts/1    00:00:00 toolbox
   4222 pts/1    00:00:28 podman
 971900 pts/1    00:00:00 bash
1100453 pts/1    00:00:00 tail
1160346 pts/1    00:00:00 bash
1179763 pts/1    00:00:00 perf-noploop
1179765 pts/1    00:00:00 ps
⬢ [acme@toolbx perf-tools-next]$

And then on one of the Alpine Linux containers:

make: Leaving directory '/tmp/perf-6.16.0-rc3/tools/perf'
/tmp/perf-6.16.0-rc3 $ cat /etc/os-release 
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.18.12
PRETTY_NAME="Alpine Linux v3.18"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"
/tmp/perf-6.16.0-rc3 $ tools/perf/perf test -w noploop &
/tmp/perf-6.16.0-rc3 $ ps
PID   USER     TIME  COMMAND
    1 toolsbui  0:00 /bin/sh
 5693 toolsbui  0:00 {perf-noploop} tools/perf/perf test -w noploop
 5694 toolsbui  0:00 ps
/tmp/perf-6.16.0-rc3 $ 
[1]+  Done                       tools/perf/perf test -w noploop
/tmp/perf-6.16.0-rc3

There are more direct use of prctl() to set the name in tools/perf/,
using pthread_setname_np() seems cleaner :-)

- Arnaldo

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Ian Rogers]

On Mon, Jun 23, 2025 at 12:19 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> On Mon, Jun 23, 2025 at 11:14:47AM -0700, Namhyung Kim wrote:
> > On Mon, Jun 23, 2025 at 11:05:41AM -0700, Ian Rogers wrote:
> > > On Mon, Jun 23, 2025 at 10:45 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> > > > On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> > > > > On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > > > > I'm afraid it'd introduce a build failure on musl.  Please see
>
> > > > > > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/
>
> > > > > > I think <sys/prctl.h> would be enough.
>
> > > > > we could do that but in the glibc man page it says:
> > > > > https://man7.org/linux/man-pages/man2/prctl.2.html
> > > > > ```
> > > > > #include <linux/prctl.h>  /* Definition of PR_* constants */
> > > > > #include <sys/prctl.h>
> > > > > ```
>
> > > > > It'd be nice to think musl was slowly getting fixed. I notice we're
>
> > > > Sebastian reported on the musl libc, its maintainer replied:
>
> > > > https://www.openwall.com/lists/musl/2025/06/12/11
>
> > > Ugh. I'm not sure how we're expected to resolve this and have glibc
> > > and musl be happy without basically not trusting libc.
>
> > Maybe pthread_setname_np()?  It seems musl also implemented it.
>
> ⬢ [acme@toolbx perf-tools-next]$ git diff
> diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
> index 8b954d4660833a2f..656e472e618822a3 100644
> --- a/tools/perf/tests/workloads/noploop.c
> +++ b/tools/perf/tests/workloads/noploop.c
> @@ -1,9 +1,8 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
> +#include <pthread.h>
>  #include <stdlib.h>
>  #include <signal.h>
>  #include <unistd.h>
> -#include <linux/prctl.h>
> -#include <sys/prctl.h>
>  #include <linux/compiler.h>
>  #include "../tests.h"
>
> @@ -18,7 +17,7 @@ static int noploop(int argc, const char **argv)
>  {
>         int sec = 1;
>
> -       prctl(PR_SET_NAME, "perf-noploop");
> +       pthread_setname_np(pthread_self(), "perf-noploop");
>         if (argc > 0)
>                 sec = atoi(argv[0]);
>
> ⬢ [acme@toolbx perf-tools-next]$
>
> ⬢ [acme@toolbx perf-tools-next]$ perf test -w noploop &
> [1] 1179763
> ⬢ [acme@toolbx perf-tools-next]$ ps
>     PID TTY          TIME CMD
>    3935 pts/1    00:00:00 bash
>    4053 pts/1    00:00:00 toolbox
>    4222 pts/1    00:00:28 podman
>  971900 pts/1    00:00:00 bash
> 1100453 pts/1    00:00:00 tail
> 1160346 pts/1    00:00:00 bash
> 1179763 pts/1    00:00:00 perf-noploop
> 1179765 pts/1    00:00:00 ps
> ⬢ [acme@toolbx perf-tools-next]$
>
> And then on one of the Alpine Linux containers:
>
> make: Leaving directory '/tmp/perf-6.16.0-rc3/tools/perf'
> /tmp/perf-6.16.0-rc3 $ cat /etc/os-release
> NAME="Alpine Linux"
> ID=alpine
> VERSION_ID=3.18.12
> PRETTY_NAME="Alpine Linux v3.18"
> HOME_URL="https://alpinelinux.org/"
> BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"
> /tmp/perf-6.16.0-rc3 $ tools/perf/perf test -w noploop &
> /tmp/perf-6.16.0-rc3 $ ps
> PID   USER     TIME  COMMAND
>     1 toolsbui  0:00 /bin/sh
>  5693 toolsbui  0:00 {perf-noploop} tools/perf/perf test -w noploop
>  5694 toolsbui  0:00 ps
> /tmp/perf-6.16.0-rc3 $
> [1]+  Done                       tools/perf/perf test -w noploop
> /tmp/perf-6.16.0-rc3
>
> There are more direct use of prctl() to set the name in tools/perf/,
> using pthread_setname_np() seems cleaner :-)

Yeah, I wanted to set the program name rather than a thread name for
the sake of seeing the process name in ps - hence reaching for prctl.
PR_SET_NAME is documented as setting the thread name and so no
difference to pthread_setname_np. It's still frustrating to get bogged
down in working around musl when typing the literal code from the
prctl man page. Do you need me to re-send the patch?

Thanks,
Ian

> - Arnaldo

Re: [PATCH v2 1/2] perf test workload noploop: Name the noploop process

[Namhyung Kim]

On Mon, Jun 23, 2025 at 12:41:09PM -0700, Ian Rogers wrote:
> On Mon, Jun 23, 2025 at 12:19 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > On Mon, Jun 23, 2025 at 11:14:47AM -0700, Namhyung Kim wrote:
> > > On Mon, Jun 23, 2025 at 11:05:41AM -0700, Ian Rogers wrote:
> > > > On Mon, Jun 23, 2025 at 10:45 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> > > > > On Mon, Jun 23, 2025 at 08:12:47AM -0700, Ian Rogers wrote:
> > > > > > On Fri, Jun 20, 2025 at 12:36 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > > > > > I'm afraid it'd introduce a build failure on musl.  Please see
> >
> > > > > > > https://lore.kernel.org/linux-perf-users/20250611092542.F4ooE2FL@linutronix.de/
> >
> > > > > > > I think <sys/prctl.h> would be enough.
> >
> > > > > > we could do that but in the glibc man page it says:
> > > > > > https://man7.org/linux/man-pages/man2/prctl.2.html
> > > > > > ```
> > > > > > #include <linux/prctl.h>  /* Definition of PR_* constants */
> > > > > > #include <sys/prctl.h>
> > > > > > ```
> >
> > > > > > It'd be nice to think musl was slowly getting fixed. I notice we're
> >
> > > > > Sebastian reported on the musl libc, its maintainer replied:
> >
> > > > > https://www.openwall.com/lists/musl/2025/06/12/11
> >
> > > > Ugh. I'm not sure how we're expected to resolve this and have glibc
> > > > and musl be happy without basically not trusting libc.
> >
> > > Maybe pthread_setname_np()?  It seems musl also implemented it.
> >
> > ⬢ [acme@toolbx perf-tools-next]$ git diff
> > diff --git a/tools/perf/tests/workloads/noploop.c b/tools/perf/tests/workloads/noploop.c
> > index 8b954d4660833a2f..656e472e618822a3 100644
> > --- a/tools/perf/tests/workloads/noploop.c
> > +++ b/tools/perf/tests/workloads/noploop.c
> > @@ -1,9 +1,8 @@
> >  /* SPDX-License-Identifier: GPL-2.0 */
> > +#include <pthread.h>
> >  #include <stdlib.h>
> >  #include <signal.h>
> >  #include <unistd.h>
> > -#include <linux/prctl.h>
> > -#include <sys/prctl.h>
> >  #include <linux/compiler.h>
> >  #include "../tests.h"
> >
> > @@ -18,7 +17,7 @@ static int noploop(int argc, const char **argv)
> >  {
> >         int sec = 1;
> >
> > -       prctl(PR_SET_NAME, "perf-noploop");
> > +       pthread_setname_np(pthread_self(), "perf-noploop");
> >         if (argc > 0)
> >                 sec = atoi(argv[0]);
> >
> > ⬢ [acme@toolbx perf-tools-next]$
> >
> > ⬢ [acme@toolbx perf-tools-next]$ perf test -w noploop &
> > [1] 1179763
> > ⬢ [acme@toolbx perf-tools-next]$ ps
> >     PID TTY          TIME CMD
> >    3935 pts/1    00:00:00 bash
> >    4053 pts/1    00:00:00 toolbox
> >    4222 pts/1    00:00:28 podman
> >  971900 pts/1    00:00:00 bash
> > 1100453 pts/1    00:00:00 tail
> > 1160346 pts/1    00:00:00 bash
> > 1179763 pts/1    00:00:00 perf-noploop
> > 1179765 pts/1    00:00:00 ps
> > ⬢ [acme@toolbx perf-tools-next]$
> >
> > And then on one of the Alpine Linux containers:
> >
> > make: Leaving directory '/tmp/perf-6.16.0-rc3/tools/perf'
> > /tmp/perf-6.16.0-rc3 $ cat /etc/os-release
> > NAME="Alpine Linux"
> > ID=alpine
> > VERSION_ID=3.18.12
> > PRETTY_NAME="Alpine Linux v3.18"
> > HOME_URL="https://alpinelinux.org/"
> > BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"
> > /tmp/perf-6.16.0-rc3 $ tools/perf/perf test -w noploop &
> > /tmp/perf-6.16.0-rc3 $ ps
> > PID   USER     TIME  COMMAND
> >     1 toolsbui  0:00 /bin/sh
> >  5693 toolsbui  0:00 {perf-noploop} tools/perf/perf test -w noploop
> >  5694 toolsbui  0:00 ps
> > /tmp/perf-6.16.0-rc3 $
> > [1]+  Done                       tools/perf/perf test -w noploop
> > /tmp/perf-6.16.0-rc3
> >
> > There are more direct use of prctl() to set the name in tools/perf/,
> > using pthread_setname_np() seems cleaner :-)
> 
> Yeah, I wanted to set the program name rather than a thread name for
> the sake of seeing the process name in ps - hence reaching for prctl.
> PR_SET_NAME is documented as setting the thread name and so no
> difference to pthread_setname_np. It's still frustrating to get bogged
> down in working around musl when typing the literal code from the
> prctl man page. Do you need me to re-send the patch?

Yes please.  And address comments in the patch 2 as well.

Thanks,
Namhyung