• Arnaldo Carvalho de Melo's avatar
    perf diff: Use perf_session__fprintf_hists just like 'perf record' · c351c281
    Arnaldo Carvalho de Melo authored
    That means that almost everything you can do with 'perf report'
    can be done with 'perf diff', for instance:
    
    $ perf record -f find / > /dev/null
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.062 MB perf.data (~2699
    samples) ] $ perf record -f find / > /dev/null
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.062 MB perf.data (~2687
    samples) ] perf diff | head -8
         9.02%     +1.00%     find  libc-2.10.1.so               [.] _IO_vfprintf_internal
         2.91%     -1.00%     find  [kernel]                     [k] __kmalloc
         2.85%     -1.00%     find  [kernel]                     [k] ext4_htree_store_dirent
         1.99%     -1.00%     find  [kernel]                     [k] _atomic_dec_and_lock
         2.44%                find  [kernel]                     [k] half_md4_transform
    $
    
    So if you want to zoom into libc:
    
    $ perf diff --dsos libc-2.10.1.so | head -8
        37.34%                find  [.] _IO_vfprintf_internal
        10.34%                find  [.] __GI_memmove
         8.25%     +2.00%     find  [.] _int_malloc
         5.07%     -1.00%     find  [.] __GI_mempcpy
         7.62%     +2.00%     find  [.] _int_free
    $
    
    And if there were multiple commands using libc, it is also
    possible to aggregate them all by using --sort symbol:
    
    $ perf diff --dsos libc-2.10.1.so --sort symbol | head -8
        37.34%             [.] _IO_vfprintf_internal
        10.34%             [.] __GI_memmove
         8.25%     +2.00%  [.] _int_malloc
         5.07%     -1.00%  [.] __GI_mempcpy
         7.62%     +2.00%  [.] _int_free
    $
    
    The displacement column now is off by default, to use it:
    
    perf diff -m --dsos libc-2.10.1.so --sort symbol | head -8
        37.34%                   [.] _IO_vfprintf_internal
        10.34%                   [.] __GI_memmove
         8.25%     +2.00%        [.] _int_malloc
         5.07%     -1.00%    +2  [.] __GI_mempcpy
         7.62%     +2.00%    -1  [.] _int_free
    $
    
    Using -t/--field-separator can be used for scripting:
    
    $ perf diff -t, -m --dsos libc-2.10.1.so --sort symbol | head -8
    37.34, , ,[.] _IO_vfprintf_internal
    10.34, , ,[.] __GI_memmove
    8.25,+2.00%, ,[.] _int_malloc
    5.07,-1.00%,  +2,[.] __GI_mempcpy
    7.62,+2.00%,  -1,[.] _int_free
    6.99,+1.00%,  -1,[.] _IO_new_file_xsputn
    1.89,-2.00%,  +4,[.] __readdir64
    $
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Frédéric Weisbecker <fweisbec@gmail.com>
    Cc: Mike Galbraith <efault@gmx.de>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Paul Mackerras <paulus@samba.org>
    LKML-Reference: <1260978567-550-1-git-send-email-acme@infradead.org>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    c351c281
perf-report.txt 1.59 KB