• Stephane Eranian's avatar
    perf inject: Add jitdump mmap injection support · 9b07e27f
    Stephane Eranian authored
    This patch adds a --jit/-j option to perf inject.
    
    This options injects MMAP records into the perf.data file to cover the
    jitted code mmaps. It also emits ELF images for each function in the
    jidump file.  Those images are created where the jitdump file is.  The
    MMAP records point to that location as well.
    
    Typical flow:
    
      $ perf record -k mono -- java -agentpath:libpjvmti.so java_class
      $ perf inject --jit -i perf.data -o perf.data.jitted
      $ perf report -i perf.data.jitted
    
    Note that jitdump.h support is not limited to Java, it works with any
    jitted environment modified to emit the jitdump file format, include
    those where code can be jitted multiple times and moved around.
    
    The jitdump.h format is adapted from the Oprofile project.
    
    The genelf.c (ELF binary generation) depends on MD5 hash encoding for
    the buildid. To enable this, libssl-dev must be installed. If not, then
    genelf.c defaults to using urandom to generate the buildid, which is not
    ideal.  The Makefile auto-detects the presence on libssl-dev.
    
    This version mmaps the jitdump file to create a marker MMAP record in
    the perf.data file. The marker is used to detect jitdump and cause perf
    inject to inject the jitted mmaps and generate ELF images for jitted
    functions.
    
    In V8, the following fixes and changes were made among other things:
    
      -  the jidump header format include a new flags field to be used
         to carry information about the configuration of the runtime agent.
         Contributed by: Adrian Hunter <adrian.hunter@intel.com>
    
      - Fix mmap pgoff: MMAP event pgoff must be the offset within the ELF file
        at which the code resides.
        Contributed by: Adrian Hunter <adrian.hunter@intel.com>
    
      - Fix ELF virtual addresses: perf tools expect the ELF virtual addresses of dynamic
        objects to match the file offset.
        Contributed by: Adrian Hunter <adrian.hunter@intel.com>
    
      - JIT MMAP injection does not obey finished_round semantics. JIT MMAP injection injects all
        MMAP events in one go, so it does not obey finished_round semantics, so drop the
        finished_round events from the output perf.data file.
        Contributed by: Adrian Hunter <adrian.hunter@intel.com>
    Signed-off-by: default avatarStephane Eranian <eranian@google.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Carl Love <cel@us.ibm.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: John McCutchan <johnmccutchan@google.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Pawel Moll <pawel.moll@arm.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Sonny Rao <sonnyrao@chromium.org>
    Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
    Link: http://lkml.kernel.org/r/1448874143-7269-3-git-send-email-eranian@google.com
    [ Moved inject.build_ids ordering bits to a separate patch, fixed the NO_LIBELF=1 build ]
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    9b07e27f
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