linux-kernel - Re: [PATCH v1 0/3] perf record: adapt NUMA awareness to machines with #CPUs

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Message-ID: <20191122132659.GG17308@krava>
Date:   Fri, 22 Nov 2019 14:26:59 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 0/3] perf record: adapt NUMA awareness to machines
 with #CPUs > 1K

On Wed, Nov 20, 2019 at 12:33:10PM +0300, Alexey Budankov wrote:
> 
> Current implementation of cpu_set_t type by glibc has internal cpu
> mask size limitation of no more than 1024 CPUs. This limitation confines
> NUMA awareness of Perf tool in record mode, thru --affinity option,
> to the first 1024 CPUs on machines with larger amount of CPUs.
> 
> This patch set enables Perf tool to overcome 1024 CPUs limitation by
> using a dedicated struct mmap_cpu_mask type and applying tool's bitmap
> API operations to manipulate affinity masks of the tool's thread and
> the mmaped data buffers.
> 
> tools bitmap API has been extended with bitmap_equal() operation
> and its implementation is derived from the kernel one.
> 
> ---
> Alexey Budankov (3):
>   tools bitmap: extend bitmap API with bitmap_equal()
>   perf mmap: declare type for cpu mask of arbitrary length
>   perf record: adapt affinity to machines with #CPUs > 1K

looks good to me, I sent some minor comments

> 
>  tools/include/linux/bitmap.h | 21 +++++++++++++++++++++
>  tools/lib/bitmap.c           | 15 +++++++++++++++
>  tools/perf/builtin-record.c  | 28 ++++++++++++++++++++++------
>  tools/perf/util/mmap.c       | 28 ++++++++++++++++++++++------
>  tools/perf/util/mmap.h       | 11 ++++++++++-
>  5 files changed, 90 insertions(+), 13 deletions(-)
> 
> ---
> Testing:
> 
>   $ tools/perf/perf record -v --affinity=cpu -- ls
>   thread mask[8]: empty
>   Using CPUID GenuineIntel-6-5E-3
>   ...
>   mmap size 528384B
>   0x7f95f8f85010: mmap mask[8]: 0
>   0x7f95f8f950d8: mmap mask[8]: 1
>   0x7f95f8fa51a0: mmap mask[8]: 2
>   0x7f95f8fb5268: mmap mask[8]: 3
>   0x7f95f8fc5330: mmap mask[8]: 4
>   0x7f95f8fd53f8: mmap mask[8]: 5
>   0x7f95f8fe54c0: mmap mask[8]: 6
>   0x7f95f8ff5588: mmap mask[8]: 7

could we add this to -vv? -v is poluted already

perhaps we should make some effort and try to consolidate -v output
for some really basic verbose, the rest would be under -vv or specialized
--debug variable .. not in scope of this patchset of course ;-)

thanks,
jirka