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linux-next/tools/perf/Documentation/perf-buildid-cache.txt
Masami Hiramatsu a50d11a10c perf buildid-cache: Add new buildid cache if update target is not cached
Add new buildid cache if the update target file is not cached.

This can happen when an old binary is replaced by new one after caching
the old one. In this case, user sees his operation just failed.

But it does not look straight, since user just pass the binary "path",
not "build-id".

  ----
  # ./perf buildid-cache --add ./perf
  (update ./perf to new binary)
  # ./perf buildid-cache --update ./perf
  ./perf wasn't in the cache
  #
  ----

This patch adds given new binary to cache if the new binary is
not cached. So we'll not see the above error.

  ----
  # ./perf buildid-cache --add ./perf
  (update ./perf to new binary)
  # ./perf buildid-cache --update ./perf
  #
  ----

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20150226065440.23912.1494.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-02-27 10:08:37 -03:00

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perf-buildid-cache(1)
=====================
NAME
----
perf-buildid-cache - Manage build-id cache.
SYNOPSIS
--------
[verse]
'perf buildid-cache <options>'
DESCRIPTION
-----------
This command manages the build-id cache. It can add and remove files to/from
the cache. In the future it should as well purge older entries, set upper
limits for the space used by the cache, etc.
OPTIONS
-------
-a::
--add=::
Add specified file to the cache.
-k::
--kcore::
Add specified kcore file to the cache. For the current host that is
/proc/kcore which requires root permissions to read. Be aware that
running 'perf buildid-cache' as root may update root's build-id cache
not the user's. Use the -v option to see where the file is created.
Note that the copied file contains only code sections not the whole core
image. Note also that files "kallsyms" and "modules" must also be in the
same directory and are also copied. All 3 files are created with read
permissions for root only. kcore will not be added if there is already a
kcore in the cache (with the same build-id) that has the same modules at
the same addresses. Use the -v option to see if a copy of kcore is
actually made.
-r::
--remove=::
Remove specified file from the cache.
-M::
--missing=::
List missing build ids in the cache for the specified file.
-u::
--update=::
Update specified file of the cache. Note that this doesn't remove
older entires since those may be still needed for annotating old
(or remote) perf.data. Only if there is already a cache which has
exactly same build-id, that is replaced by new one. It can be used
to update kallsyms and kernel dso to vmlinux in order to support
annotation.
-v::
--verbose::
Be more verbose.
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-report[1], linkperf:perf-buildid-list[1]