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    SubjectRe: [PATCH v2 5/5] perf: make perf buildid-list work better with pipe mode
    On 5/15/12 5:28 AM, Stephane Eranian wrote:
    > In order for perf buildid-list to work with pipe-mode files,
    > it needs to process buildids and event attr structs.
    >
    > $ perf record -o - noploop 2 | ./perf inject -b | perf buildid-list -i - -H
    > noploop for 2 seconds
    > [ perf record: Woken up 1 times to write data ]
    > [ perf record: Captured and wrote 0.084 MB - (~3678 samples) ]
    > 0000000000000000000000000000000000000000 [kernel.kallsyms]
    > 3a0d0629efe74a8da3eeba372cdbd74ad9b8f5d5 /usr/local/bin/noploop
    >
    > The reason [kernel.kallsyms] shows a 0 build-id comes from the
    > way buildids are injected in the stream. The buildid for the kernel
    > is provided by a BUILD_ID record. The [kernel.kallsyms] is provided
    > by a MMAP record. There is no clean and obvious way to link the two,
    > unfortunately. In regular mode, the kernel buildid is generated from
    > reading the ELF image or kallsyms and perf knows to associate
    > [kernel.kallsyms] to it. Later on, when perf processes the
    > [kernel.kallsyms] MMAP record, it will already have a dso for it.
    >
    > So for now, make sure perf buildid-list shows the buildids for
    > everything but the kernel image.
    >
    > Signed-off-by: Stephane Eranian<eranian@google.com>
    > ---
    > tools/perf/builtin-buildid-list.c | 6 +++++-
    > tools/perf/util/build-id.c | 2 ++
    > 2 files changed, 7 insertions(+), 1 deletions(-)

    Reviewed-and-tested-by: David Ahern <dsahern@gmail.com>


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