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2b62b3a611
Add a new "metric-id" term to events so that metric parsing can set an
ID that can be reliably looked up.
Metric parsing currently will turn a metric like "instructions/cycles"
into a parse events string of "{instructions,cycles}:W".
However, parse-events may change "instructions" into "instructions:u" if
perf_event_paranoid=2.
When this happens expr__resolve_id currently fails as stat-shadow adds
the ID "instructions:u" to match with the counter value and the metric
tries to look up the ID just "instructions".
A later patch will use the new term.
An example of the current problem:
$ echo -1 > /proc/sys/kernel/perf_event_paranoid
$ perf stat -M IPC /bin/true
Performance counter stats for '/bin/true':
1,217,161 inst_retired.any # 0.97 IPC
1,250,389 cpu_clk_unhalted.thread
0.002064773 seconds time elapsed
0.002378000 seconds user
0.000000000 seconds sys
$ echo 2 > /proc/sys/kernel/perf_event_paranoid
$ perf stat -M IPC /bin/true
Performance counter stats for '/bin/true':
150,298 inst_retired.any:u # nan IPC
187,095 cpu_clk_unhalted.thread:u
0.002042731 seconds time elapsed
0.000000000 seconds user
0.002377000 seconds sys
Note: nan IPC is printed as an effect of "perf metric: Use NAN for
missing event IDs." but earlier versions of perf just fail with a parse
error and display no value.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Kilroy <andrew.kilroy@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Denys Zagorui <dzagorui@cisco.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: ShihCheng Tu <mrtoastcheng@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Wan Jiabing <wanjiabing@vivo.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20211015172132.1162559-15-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.