From: Wyes Karny <wyes.karny@amd.com>
To: Doug Smythies <dsmythies@telus.net>
Cc: lenb@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tools/power turbostat: Increase the limit for fd opened
Date: Wed, 27 Sep 2023 10:46:17 +0530 [thread overview]
Message-ID: <ZRO6ofa9sHbKJBCv@BLR-5CG13462PL.amd.com> (raw)
In-Reply-To: <004501d9ed96$16af12f0$440d38d0$@telus.net>
Hi Doug,
Thanks for taking a look at the patch.
On 22 Sep 13:48, Doug Smythies wrote:
> On 2023.09.22 02:28 Wyes Karny wrote:
>
> > When running turbostat, a system with 512 cpus reaches the limit for
>
> Suggest" ... reaches the default limit for..."
>
> > maximum number of file descriptors that can be opened. To solve this
> > problem, the limit is raised to 2^15, which is a large enough number.
> >
> > Below data is collected from AMD server systems while running turbostat:
> >
> > |-----------+-------------------------------|
> > | # of cpus | # of opened fds for turbostat |
> > |-----------+-------------------------------|
> > | 128 | 260 |
> > |-----------+-------------------------------|
> > | 192 | 388 |
> > |-----------+-------------------------------|
> > | 512 | 1028 |
> > |-----------+-------------------------------|
>
> The number of open files is a function of what is being "show"ed or "hide"en.
> They can also increase beyond the above 2 X (# of CPUs) + 4 number
> via the --add directive.
> >
> > So, the new max limit would be sufficient up to 2^14 cpus.
>
> Well, not quiet, but the point is valid.
>
> Normally, I would assume that a server with a large number of
> CPUs would have set a much higher limit of the number of open
> files than the default. I use 131,072 and so this patch reduces the
> maximum.
I think below will fix the problem.
+#define MAX_NOFILE 0x8000
+
+void set_rlimit(void)
+{
+ struct rlimit limit;
+
+ if(getrlimit(RLIMIT_NOFILE, &limit) < 0) {
+ err(1, "Failed to get rlimit");
+ }
+
+ if (limit.rlim_max < MAX_NOFILE)
+ limit.rlim_max = MAX_NOFILE;
+ if (limit.rlim_cur < MAX_NOFILE)
+ limit.rlim_cur = MAX_NOFILE;
+
+ if (setrlimit(RLIMIT_NOFILE, &limit) < 0) {
+ err(1, "Failed to set rlimit");
+ }
+ return;
+}
Is this looks okay to you?
Thanks,
Wyes
>
> Unpatched:
> root@s19:~# cat /proc/47043/limits | grep "Max open files"
> Max open files 131072 131072 files
>
> Patched:
> root@s19:~# cat /proc/47032/limits | grep "Max open files"
> Max open files 32768 32768 files
>
> Anyway:
>
> Reviewed-by: Doug Smythies <dsmythies@telus.net>
> Tested-by: Doug Smythies <dsmythies@telus.net>
>
> >
> > Signed-off-by: Wyes Karny <wyes.karny@amd.com>
> > ---
> > tools/power/x86/turbostat/turbostat.c | 15 +++++++++++++++
> > 1 file changed, 15 insertions(+)
> >
> > diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> > index 9a10512e3407..23f1fe58289a 100644
> > --- a/tools/power/x86/turbostat/turbostat.c
> > +++ b/tools/power/x86/turbostat/turbostat.c
> > @@ -6717,6 +6717,18 @@ void cmdline(int argc, char **argv)
> > }
> > }
> >
> > +void set_rlimit(void)
> > +{
> > + struct rlimit limit;
> > +
> > + limit.rlim_cur = 0x8000;
> > + limit.rlim_max = 0x8000;
> > +
> > + if (setrlimit(RLIMIT_NOFILE, &limit) < 0) {
> > + err(1, "Failed to set rlimit");
> > + }
> > +}
> > +
> > int main(int argc, char **argv)
> > {
> > outf = stderr;
> > @@ -6729,6 +6741,9 @@ int main(int argc, char **argv)
> >
> > probe_sysfs();
> >
> > + if (!getuid())
> > + set_rlimit();
> > +
> > turbostat_init();
> >
> > msr_sum_record();
> > --
> > 2.34.1
> >
>
next prev parent reply other threads:[~2023-09-27 5:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 9:28 [PATCH] tools/power turbostat: Increase the limit for fd opened Wyes Karny
2023-09-22 20:48 ` Doug Smythies
2023-09-27 5:16 ` Wyes Karny [this message]
2023-09-29 15:32 ` Doug Smythies
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