b91e5492f9
Some symbols may not be resolved if a user only monitors one type of
PMU.
$ sudo perf record -e cpu_atom/branch-instructions/ ./big_small_workload
$ sudo perf report –stdio
# Overhead Command Shared Object Symbol
# ........ ......... ................. .....................
#
28.02% perf-exec [unknown] [.] 0x0000000000401cf6
11.32% perf-exec [unknown] [.] 0x0000000000401d04
10.90% perf-exec [unknown] [.] 0x0000000000401d11
10.61% perf-exec [unknown] [.] 0x0000000000401cfc
To parse symbols the metadata records, e.g., PERF_RECORD_COMM, which are
generated by the kernel, are required.
To decide whether to generate the metadata records, the kernel relies on
the event_filter_match() to filter the unrelated events.
On a hybrid system, event_filter_match() further checks the CPU mask of
the current enabled PMU. If an event is collected on the CPU which
doesn't have an enabled PMU, it's treated as an unrelated event.
The "big_small_workload" is created in a big core, but runs on a small
core. The metadata records are filtered, because the user only monitors
the PMU of the small core. The big core PMU is not enabled.
For a hybrid system, a dummy event is required to generate the complete
side-band events.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/1625760212-18441-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
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|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.