• Lin Ming's avatar
    perf probe: Add fastpath to do lookup by function name · cd25f8bc
    Lin Ming authored
    v3 -> v2:
    - Make pubname_search_cb more generic
    - Add fastpath to find_probes also
    
    v2 -> v1:
    - Don't compare file names with cu_find_realpath(...), instead, compare
      them with the name returned by dwarf_decl_file(sp_die)
    
    The vmlinux file may have thousands of CUs.
    We can lookup function name from .debug_pubnames section
    to avoid the slow loop on CUs.
    
    1. Improvement data for find_line_range
    
    ./perf stat -e cycles -r 10 -- ./perf probe -k /home/mlin/vmlinux \
            -s /home/mlin/linux-2.6 \
            --line csum_partial_copy_to_user > tmp.log
    
    before patch applied
    =====================
           847,988,276 cycles
    
            0.355075856  seconds time elapsed
    
    after patch applied
    =====================
           206,102,622 cycles
    
            0.086883555  seconds time elapsed
    
    2. Improvement data for find_probes
    
    ./perf stat -e cycles -r 10 -- ./perf probe -k /home/mlin/vmlinux \
            -s /home/mlin/linux-2.6 \
            --vars csum_partial_copy_to_user > tmp.log
    
    before patch applied
    =====================
           848,490,844 cycles
    
            0.355307901  seconds time elapsed
    
    after patch applied
    =====================
           205,684,469 cycles
    
            0.086694010  seconds time elapsed
    Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: linux-kernel <linux-kernel@vger.kernel.org>
    LKML-Reference: <1301041668.14111.52.camel@minggr.sh.intel.com>
    Signed-off-by: default avatarLin Ming <ming.m.lin@intel.com>
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    cd25f8bc
probe-finder.c 48.7 KB