linux-stable/tools/perf/Documentation/perf-buildid-cache.txt
Jiri Olsa 9bce13ea88 perf record: Disable debuginfod by default
Fedora 35 sets DEBUGINFOD_URLS by default, which might lead to
unexpected stalls in perf record exit path, when we try to cache
profiled binaries.

  # DEBUGINFOD_PROGRESS=1 ./perf record -a
  ^C[ perf record: Woken up 1 times to write data ]
  Downloading from https://debuginfod.fedoraproject.org/ 447069
  Downloading from https://debuginfod.fedoraproject.org/ 1502175
  Downloading \^Z

Disabling DEBUGINFOD_URLS by default in perf record and adding
debuginfod option and .perfconfig variable support to enable id.

  Default without debuginfo processing:
  # perf record -a

  Using system debuginfod setup:
  # perf record -a --debuginfod

  Using custom debuginfd url:
  # perf record -a --debuginfod='https://evenbetterdebuginfodserver.krava'

Adding single perf_debuginfod_setup function and using
it also in perf buildid-cache command.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20211209200425.303561-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-01-15 17:41:25 -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, remove, update and purge
files to/from the cache. In the future it should as well set upper limits for
the space used by the cache, etc.
This also scans the target binary for SDT (Statically Defined Tracing) and
record it along with the buildid-cache, which will be used by perf-probe.
For more details, see linkperf:perf-probe[1].
OPTIONS
-------
-a::
--add=::
Add specified file to the cache.
-f::
--force::
Don't complain, do it.
-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 a cached binary which has same build-id of specified file
from the cache.
-p::
--purge=::
Purge all cached binaries including older caches which have specified
path from the cache.
-P::
--purge-all::
Purge all cached binaries. This will flush out entire 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 entries 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.
-l::
--list::
List all valid binaries from cache.
-v::
--verbose::
Be more verbose.
--target-ns=PID:
Obtain mount namespace information from the target pid. This is
used when creating a uprobe for a process that resides in a
different mount namespace from the perf(1) utility.
--debuginfod[=URLs]::
Specify debuginfod URL to be used when retrieving perf.data binaries,
it follows the same syntax as the DEBUGINFOD_URLS variable, like:
buildid-cache.debuginfod=http://192.168.122.174:8002
If the URLs is not specified, the value of DEBUGINFOD_URLS
system environment variable is used.
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-report[1], linkperf:perf-buildid-list[1]