linux-kernel - Re: [PATCH v2] perf: Increase MAX_NR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAP-5=fVQnXM2c7dH=kfDu4AzN2mQs5G1zXZoopTs7Dco+bHi+A@mail.gmail.com>
Date: Thu, 5 Dec 2024 20:27:45 -0800
From: Ian Rogers <irogers@...gle.com>
To: Kyle Meyer <kyle.meyer@....com>
Cc: peterz@...radead.org, mingo@...hat.com, acme@...nel.org, 
	namhyung@...nel.org, mark.rutland@....com, alexander.shishkin@...ux.intel.com, 
	jolsa@...nel.org, adrian.hunter@...el.com, kan.liang@...ux.intel.com, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] perf: Increase MAX_NR_CPUS to 4096

On Thu, Dec 5, 2024 at 1:07 PM Kyle Meyer <kyle.meyer@....com> wrote:
>
> Systems have surpassed 2048 CPUs. Increase MAX_NR_CPUS to 4096.
>
> Bitmaps declared with MAX_NR_CPUS bits will increase from 256B to 512B,
> cpus_runtime will increase from 81960B to 163880B, and max_entries will
> increase from 8192B to 16384B.
>
> Signed-off-by: Kyle Meyer <kyle.meyer@....com>

Reviewed-by: Ian Rogers <irogers@...gle.com>

Thanks,
Ian

> ---
>
> v1 -> v2:
>   * Increase MAX_NR_CPUS in tools/perf/util/bpf_skel/kwork_top.bpf.c, as
>     suggested by Ian Rogers.
>   * https://lore.kernel.org/all/20241205165118.153148-1-kyle.meyer@hpe.com/
>
>  tools/lib/perf/include/internal/cpumap.h | 2 +-
>  tools/perf/perf.h                        | 2 +-
>  tools/perf/util/bpf_skel/kwork_top.bpf.c | 4 +++-
>  3 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/tools/lib/perf/include/internal/cpumap.h b/tools/lib/perf/include/internal/cpumap.h
> index 49649eb51ce4..3cf28522004e 100644
> --- a/tools/lib/perf/include/internal/cpumap.h
> +++ b/tools/lib/perf/include/internal/cpumap.h
> @@ -22,7 +22,7 @@ DECLARE_RC_STRUCT(perf_cpu_map) {
>  };
>
>  #ifndef MAX_NR_CPUS
> -#define MAX_NR_CPUS    2048
> +#define MAX_NR_CPUS    4096
>  #endif
>
>  struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus);
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index c004dd4e65a3..3cb40965549f 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -3,7 +3,7 @@
>  #define _PERF_PERF_H
>
>  #ifndef MAX_NR_CPUS
> -#define MAX_NR_CPUS                    2048
> +#define MAX_NR_CPUS                    4096
>  #endif
>
>  enum perf_affinity {
> diff --git a/tools/perf/util/bpf_skel/kwork_top.bpf.c b/tools/perf/util/bpf_skel/kwork_top.bpf.c
> index 594da91965a2..73e32e063030 100644
> --- a/tools/perf/util/bpf_skel/kwork_top.bpf.c
> +++ b/tools/perf/util/bpf_skel/kwork_top.bpf.c
> @@ -18,7 +18,9 @@ enum kwork_class_type {
>  };
>
>  #define MAX_ENTRIES     102400
> -#define MAX_NR_CPUS     2048
> +#ifndef MAX_NR_CPUS
> +#define MAX_NR_CPUS     4096
> +#endif
>  #define PF_KTHREAD      0x00200000
>  #define MAX_COMMAND_LEN 16
>
> --
> 2.35.3
>