493be70ac3
If we run a single workload that only runs on big core, there is always
a ugly message about disabling the NMI watchdog because the atom is not
counted.
Before:
# ./perf stat true
Performance counter stats for 'true':
0.43 msec task-clock # 0.396 CPUs utilized
0 context-switches # 0.000 /sec
0 cpu-migrations # 0.000 /sec
45 page-faults # 103.918 K/sec
639,634 cpu_core/cycles/ # 1.477 G/sec
<not counted> cpu_atom/cycles/ (0.00%)
643,498 cpu_core/instructions/ # 1.486 G/sec
<not counted> cpu_atom/instructions/ (0.00%)
123,715 cpu_core/branches/ # 285.694 M/sec
<not counted> cpu_atom/branches/ (0.00%)
4,094 cpu_core/branch-misses/ # 9.454 M/sec
<not counted> cpu_atom/branch-misses/ (0.00%)
0.001092407 seconds time elapsed
0.001144000 seconds user
0.000000000 seconds sys
Some events weren't counted. Try disabling the NMI watchdog:
echo 0 > /proc/sys/kernel/nmi_watchdog
perf stat ...
echo 1 > /proc/sys/kernel/nmi_watchdog
# ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
Performance counter stats for 'true':
<not counted> cpu_atom/cycles/ (0.00%)
<not counted> msr/tsc/ (0.00%)
0.001904106 seconds time elapsed
0.001947000 seconds user
0.000000000 seconds sys
Some events weren't counted. Try disabling the NMI watchdog:
echo 0 > /proc/sys/kernel/nmi_watchdog
perf stat ...
echo 1 > /proc/sys/kernel/nmi_watchdog
The events in group usually have to be from the same PMU. Try reorganizing the group.
Now we disable the NMI watchdog message on hybrid, otherwise there
are too many false positives.
After:
# ./perf stat true
Performance counter stats for 'true':
0.79 msec task-clock # 0.419 CPUs utilized
0 context-switches # 0.000 /sec
0 cpu-migrations # 0.000 /sec
48 page-faults # 60.889 K/sec
777,692 cpu_core/cycles/ # 986.519 M/sec
<not counted> cpu_atom/cycles/ (0.00%)
669,147 cpu_core/instructions/ # 848.828 M/sec
<not counted> cpu_atom/instructions/ (0.00%)
128,635 cpu_core/branches/ # 163.176 M/sec
<not counted> cpu_atom/branches/ (0.00%)
4,089 cpu_core/branch-misses/ # 5.187 M/sec
<not counted> cpu_atom/branch-misses/ (0.00%)
0.001880649 seconds time elapsed
0.001935000 seconds user
0.000000000 seconds sys
# ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
Performance counter stats for 'true':
<not counted> cpu_atom/cycles/ (0.00%)
<not counted> msr/tsc/ (0.00%)
0.000963319 seconds time elapsed
0.000999000 seconds user
0.000000000 seconds sys
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210610034557.29766-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
||
|---|---|---|
| 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.