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    Subject[PATCH 47/91] perf intel-pt: Update documentation about using /proc/kcore
    Date
    From: Adrian Hunter <adrian.hunter@intel.com>

    Update documentation to reflect the advent of the --kcore option for
    'perf record'.

    Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Link: http://lore.kernel.org/lkml/20200429150751.12570-10-adrian.hunter@intel.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    ---
    tools/perf/Documentation/perf-intel-pt.txt | 18 +++++++++---------
    1 file changed, 9 insertions(+), 9 deletions(-)

    diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
    index 782eb8a65caf..eb8b7d42591a 100644
    --- a/tools/perf/Documentation/perf-intel-pt.txt
    +++ b/tools/perf/Documentation/perf-intel-pt.txt
    @@ -69,22 +69,22 @@ And profiled with 'perf report' e.g.
    To also trace kernel space presents a problem, namely kernel self-modifying
    code. A fairly good kernel image is available in /proc/kcore but to get an
    accurate image a copy of /proc/kcore needs to be made under the same conditions
    -as the data capture. A script perf-with-kcore can do that, but beware that the
    -script makes use of 'sudo' to copy /proc/kcore. If you have perf installed
    -locally from the source tree you can do:
    +as the data capture. 'perf record' can make a copy of /proc/kcore if the option
    +--kcore is used, but access to /proc/kcore is restricted e.g.

    - ~/libexec/perf-core/perf-with-kcore record pt_ls -e intel_pt// -- ls
    + sudo perf record -o pt_ls --kcore -e intel_pt// -- ls

    -which will create a directory named 'pt_ls' and put the perf.data file and
    -copies of /proc/kcore, /proc/kallsyms and /proc/modules into it. Then to use
    -'perf report' becomes:
    +which will create a directory named 'pt_ls' and put the perf.data file (named
    +simply 'data') and copies of /proc/kcore, /proc/kallsyms and /proc/modules into
    +it. The other tools understand the directory format, so to use 'perf report'
    +becomes:

    - ~/libexec/perf-core/perf-with-kcore report pt_ls
    + sudo perf report -i pt_ls

    Because samples are synthesized after-the-fact, the sampling period can be
    selected for reporting. e.g. sample every microsecond

    - ~/libexec/perf-core/perf-with-kcore report pt_ls --itrace=i1usge
    + sudo perf report pt_ls --itrace=i1usge

    See the sections below for more information about the --itrace option.

    --
    2.21.1
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