Re: [PATCHv2 0/2] perf tools: Share struct map after clone

[Jiri Olsa]

On Wed, Oct 16, 2019 at 10:22:24AM +0200, Jiri Olsa wrote:
> hi,
> Andi reported that maps cloning is eating lot of memory and
> it's probably unnecessary, because they keep the same data.
> 
> This 'maps sharing' seems to save lot of heap for reports with
> many forks/cloned mmaps (over 60% in example below).
> 
> Profile kernel build:
> 
>   $ perf record make -j 40
> 
> Get heap profile (tools/perf directory):
> 
>   $ <install gperftools>
>   $ make TCMALLOC=1
>   $ HEAPPROFILE=/tmp/heapprof ./perf report -i perf.data --stdio > out
>   $ pprof ./perf /tmp/heapprof.000*
> 
> Before:
> 
>   (pprof) top
>   Total: 2335.5 MB
>     1735.1  74.3%  74.3%   1735.1  74.3% memdup
>      402.0  17.2%  91.5%    402.0  17.2% zalloc
>      140.2   6.0%  97.5%    145.8   6.2% map__new
>       33.6   1.4%  98.9%     33.6   1.4% symbol__new
>       12.4   0.5%  99.5%     12.4   0.5% alloc_event
>        6.2   0.3%  99.7%      6.2   0.3% nsinfo__new
>        5.5   0.2% 100.0%      5.5   0.2% nsinfo__copy
>        0.3   0.0% 100.0%      0.3   0.0% dso__new
>        0.1   0.0% 100.0%      0.1   0.0% do_read_string
>        0.0   0.0% 100.0%      0.0   0.0% __GI__IO_file_doallocate
> 
> After:
> 
>   (pprof) top
>   Total: 784.5 MB
>      385.8  49.2%  49.2%    385.8  49.2% memdup
>      285.8  36.4%  85.6%    285.8  36.4% zalloc
>       80.4  10.3%  95.9%     83.7  10.7% map__new
>       19.1   2.4%  98.3%     19.1   2.4% symbol__new
>        6.2   0.8%  99.1%      6.2   0.8% alloc_event
>        3.6   0.5%  99.6%      3.6   0.5% nsinfo__new
>        3.2   0.4% 100.0%      3.2   0.4% nsinfo__copy
>        0.2   0.0% 100.0%      0.2   0.0% dso__new
>        0.0   0.0% 100.0%      0.0   0.0% do_read_string
>        0.0   0.0% 100.0%      0.0   0.0% elf_fill
> 
> v2 changes:
>   - rebased to Arnaldo's perf/core
>   - patch 1 already taken
> 
> Also available in here:
>   git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
>   perf/map_shared

I rebased to latest perf/core and pushed the branch out

jirka