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Linux kernel source tree
6e4b398770
When 'perf sched' enables the call-graph recording, sample_type of dummy
event does not have PERF_SAMPLE_CALLCHAIN, timehist_check_attr() checks
that the evsel does not have a callchain, and set show_callchain to 0.
Currently 'perf sched timehist' only saves callchain when processing the
'sched:sched_switch event', timehist_check_attr() only needs to determine
whether the event has PERF_SAMPLE_CALLCHAIN.
Before:
# perf sched record -g true
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data (7536 samples) ]
# perf sched timehist
Samples do not have callchains.
time cpu task name wait time sch delay run time
[tid/pid] (msec) (msec) (msec)
--------------- ------ ------------------------------ --------- --------- ---------
147851.826019 [0000] perf[285035] 0.000 0.000 0.000
147851.826029 [0000] migration/0[15] 0.000 0.003 0.009
147851.826063 [0001] perf[285035] 0.000 0.000 0.000
147851.826069 [0001] migration/1[21] 0.000 0.003 0.006
<SNIP>
After:
# perf sched record -g true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.572 MB perf.data (822 samples) ]
# perf sched timehist
time cpu task name waittime sch delay runtime
[tid/pid] (msec) (msec) (msec)
----------- --- --------------- -------- -------- -----
4193.035164 [0] perf[277062] 0.000 0.000 0.000 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- preempt_schedule_common <- __cond_resched <- __wait_for_common <- wait_for_completion
4193.035174 [0] migration/0[15] 0.000 0.003 0.009 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- smpboot_thread_fn <- kthread <- ret_from_fork
4193.035207 [1] perf[277062] 0.000 0.000 0.000 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- preempt_schedule_common <- __cond_resched <- __wait_for_common <- wait_for_completion
4193.035214 [1] migration/1[21] 0.000 0.003 0.007 __traceiter_sched_switch <- __traceiter_sched_switch <- __sched_text_start <- smpboot_thread_fn <- kthread <- ret_from_fork
<SNIP>
Fixes:
|
||
|---|---|---|
| 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.