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From:   Wyes Karny <wyes.karny@amd.com>
To:     <lenb@kernel.org>
CC:     Wyes Karny <wyes.karny@amd.com>, <linux-pm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Doug Smythies <dsmythies@telus.net>, <rafael@kernel.org>
Subject: Re: [PATCH v2] tools/power turbostat: Increase the limit for fd opened
Date:   Thu, 2 Nov 2023 20:31:20 +0530
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Gentle ping.

Thanks,
Wyes

On 03 Oct 05:07, Wyes Karny wrote:
> When running turbostat, a system with 512 cpus reaches the 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                          |
> |-----------+-------------------------------|
> 
> So, the new max limit would be sufficient up to 2^14 cpus (but this
> also depends on how many counters are enabled).
> 
> Reviewed-by: Doug Smythies <dsmythies@telus.net>
> Tested-by: Doug Smythies <dsmythies@telus.net>
> Signed-off-by: Wyes Karny <wyes.karny@amd.com>
> ---
> v1 -> v2:
> - Take care of already higher rlim_max, rlim_curr
> - Minor tweak in commit text
> 
>  tools/power/x86/turbostat/turbostat.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> index 9a10512e3407..1563a0ae7e4c 100644
> --- a/tools/power/x86/turbostat/turbostat.c
> +++ b/tools/power/x86/turbostat/turbostat.c
> @@ -53,6 +53,8 @@
>  #define	NAME_BYTES 20
>  #define PATH_BYTES 128
>  
> +#define MAX_NOFILE 0x8000
> +
>  enum counter_scope { SCOPE_CPU, SCOPE_CORE, SCOPE_PACKAGE };
>  enum counter_type { COUNTER_ITEMS, COUNTER_CYCLES, COUNTER_SECONDS, COUNTER_USEC };
>  enum counter_format { FORMAT_RAW, FORMAT_DELTA, FORMAT_PERCENT };
> @@ -6717,6 +6719,22 @@ void cmdline(int argc, char **argv)
>  	}
>  }
>  
> +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");
> +}
> +
>  int main(int argc, char **argv)
>  {
>  	outf = stderr;
> @@ -6729,6 +6747,9 @@ int main(int argc, char **argv)
>  
>  	probe_sysfs();
>  
> +	if (!getuid())
> +		set_rlimit();
> +
>  	turbostat_init();
>  
>  	msr_sum_record();
> -- 
> 2.34.1
>