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    perf unwind: Check the target platform before assigning unwind methods · d64ec10e
    He Kuang 提交于
    Currently, 'perf script' uses host unwind methods to parse perf.data
    callchain info without taking the target architecture into account, i.e.
    assuming the perf.data file was generated on the same machine where the
    analysis is being performed. So we get wrong result without any warnings
    when unwinding callchains of x86(32-bit) on x86(64-bit) machine.
    
    This patch adds an extra step that checks the target platform before
    assigning unwind methods. In later patches in this series, we can use
    this info to assign the right unwind methods for supported platforms.
    
    Committer note:
    
    After fixing it to register the local unwinder for live mode tools
    ('perf trace', 'perf top'), i.e. tools that don't use a perf.data file,
    it works as intended and passes the 'perf test unwind' test:
    
      # perf trace -e nanosleep --call dwarf usleep 1
         0.328 ( 0.058 ms): usleep/11115 nanosleep(rqtp: 0x7fff083fa480) = 0
                                           __nanosleep_nocancel+0x7 (/usr/lib64/libc-2.22.so)
                                           usleep+0x34 (/usr/lib64/libc-2.22.so)
                                           main+0x1eb (/usr/bin/usleep)
                                           __libc_start_main+0xf0 (/usr/lib64/libc-2.22.so)
                                           _start+0x29 (/usr/bin/usleep)
      # perf test 48
      48: Test dwarf unwind         : Ok
      #
    Signed-off-by: NHe Kuang <hekuang@huawei.com>
    Acked-by: NJiri Olsa <jolsa@kernel.org>
    Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Kan Liang <kan.liang@intel.com>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
    Cc: Wang Nan <wangnan0@huawei.com>
    Link: http://lkml.kernel.org/r/1464924803-22214-11-git-send-email-hekuang@huawei.com
    [ Fixed exit path for 'live' mode tools, where we need to default to local unwinding ]
    Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
    d64ec10e
thread.c 5.7 KB