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Sometimes it's useful to organize member fields in cache-line boundary.
The 'typecln' sort key is short for type-cacheline and to show samples
in each cacheline. The cacheline size is fixed to 64 for now, but it
can read the actual size once it saves the value from sysfs.
For example, you maybe want to which cacheline in a target is hot or
cold. The following shows members in the cfs_rq's first cache line.
$ perf report -s type,typecln,typeoff -H
...
- 2.67% struct cfs_rq
+ 1.23% struct cfs_rq: cache-line 2
+ 0.57% struct cfs_rq: cache-line 4
+ 0.46% struct cfs_rq: cache-line 6
- 0.41% struct cfs_rq: cache-line 0
0.39% struct cfs_rq +0x14 (h_nr_running)
0.02% struct cfs_rq +0x38 (tasks_timeline.rb_leftmost)
...
Committer testing:
# root@number:~# perf report -s type,typecln,typeoff -H --stdio
# Total Lost Samples: 0
#
# Samples: 5K of event 'cpu_atom/mem-loads,ldlat=5/P'
# Event count (approx.): 312251
#
# Overhead Data Type / Data Type Cacheline / Data Type Offset
# .............. ..................................................
#
<SNIP>
0.07% struct sigaction
0.05% struct sigaction: cache-line 1
0.02% struct sigaction +0x58 (sa_mask)
0.02% struct sigaction +0x78 (sa_mask)
0.03% struct sigaction: cache-line 0
0.02% struct sigaction +0x38 (sa_mask)
0.01% struct sigaction +0x8 (sa_mask)
<SNIP>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240819233603.54941-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 reStructuredText 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.