Revision tags: v6.6.67, v6.6.66, v6.6.65, v6.6.64, v6.6.63, v6.6.62, v6.6.61, v6.6.60, v6.6.59, v6.6.58, v6.6.57, v6.6.56, v6.6.55, v6.6.54, v6.6.53, v6.6.52, v6.6.51, v6.6.50, v6.6.49, v6.6.48, v6.6.47, v6.6.46, v6.6.45, v6.6.44, v6.6.43, v6.6.42, v6.6.41, v6.6.40, v6.6.39, v6.6.38, v6.6.37, v6.6.36, v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9, v6.6.8, v6.6.7, v6.6.6, v6.6.5, v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3, v6.5.2, v6.1.51, v6.5.1, v6.1.50, v6.5, v6.1.49, v6.1.48, v6.1.46, v6.1.45, v6.1.44, v6.1.43, v6.1.42, v6.1.41, v6.1.40, v6.1.39, v6.1.38, v6.1.37, v6.1.36, v6.4, v6.1.35, v6.1.34, v6.1.33, v6.1.32, v6.1.31, v6.1.30, v6.1.29, v6.1.28, v6.1.27, v6.1.26, v6.3, v6.1.25, v6.1.24, v6.1.23, v6.1.22, v6.1.21, v6.1.20, v6.1.19, v6.1.18, v6.1.17, v6.1.16, v6.1.15, v6.1.14, v6.1.13, v6.2, v6.1.12, v6.1.11, v6.1.10, v6.1.9, v6.1.8, v6.1.7, v6.1.6, v6.1.5, v6.0.19, v6.0.18, v6.1.4, v6.1.3, v6.0.17, v6.1.2, v6.0.16, v6.1.1, v6.0.15, v6.0.14, v6.0.13, v6.1, v6.0.12, v6.0.11, v6.0.10, v5.15.80, v6.0.9, v5.15.79, v6.0.8, v5.15.78, v6.0.7, v5.15.77, v5.15.76, v6.0.6, v6.0.5, v5.15.75, v6.0.4, v6.0.3, v6.0.2, v5.15.74, v5.15.73, v6.0.1, v5.15.72, v6.0, v5.15.71, v5.15.70, v5.15.69, v5.15.68, v5.15.67, v5.15.66, v5.15.65, v5.15.64, v5.15.63, v5.15.62, v5.15.61, v5.15.60, v5.15.59, v5.19, v5.15.58, v5.15.57, v5.15.56, v5.15.55, v5.15.54, v5.15.53, v5.15.52, v5.15.51, v5.15.50, v5.15.49, v5.15.48, v5.15.47, v5.15.46, v5.15.45 |
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03ab8e62 |
| 31-May-2022 |
Konstantin Komarov <almaz.alexandrovich@paragon-software.com> |
Merge tag 'v5.18'
Linux 5.18
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Revision tags: v5.15.44, v5.15.43, v5.15.42, v5.18, v5.15.41, v5.15.40, v5.15.39, v5.15.38, v5.15.37, v5.15.36, v5.15.35, v5.15.34, v5.15.33, v5.15.32, v5.15.31, v5.17, v5.15.30, v5.15.29, v5.15.28, v5.15.27, v5.15.26 |
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#
1136fa0c |
| 01-Mar-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.17-rc4' into for-linus
Merge with mainline to get the Intel ASoC generic helpers header and other changes.
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Revision tags: v5.15.25, v5.15.24, v5.15.23, v5.15.22, v5.15.21, v5.15.20, v5.15.19, v5.15.18, v5.15.17, v5.4.173, v5.15.16 |
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87a0b2fa |
| 17-Jan-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.16' into next
Sync up with mainline to bring in the latest API changes.
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Revision tags: v5.15.15 |
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762f99f4 |
| 15-Jan-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 5.17 merge window.
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Revision tags: v5.16 |
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f81483aa |
| 05-Jan-2022 |
Takashi Iwai <tiwai@suse.de> |
Merge branch 'for-next' into for-linus
Pull 5.17 materials.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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#
17580470 |
| 17-Dec-2021 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next-fixes
Backmerging to bring drm-misc-next-fixes up to the latest state for the current release cycle.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v5.15.10, v5.15.9, v5.15.8 |
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86329873 |
| 09-Dec-2021 |
Daniel Lezcano <daniel.lezcano@linaro.org> |
Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next
"Add optional variant of of_reset_control_get_exclusive(). If the requested reset is not
Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next
"Add optional variant of of_reset_control_get_exclusive(). If the requested reset is not specified in the device tree, this function returns NULL instead of an error."
This dependency is needed for the Generic Timer Module (a.k.a OSTM) support for RZ/G2L.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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5d8dfaa7 |
| 09-Dec-2021 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.15' into next
Sync up with the mainline to get the latest APIs and DT bindings.
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Revision tags: v5.15.7, v5.15.6, v5.15.5 |
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448cc2fb |
| 22-Nov-2021 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync up with drm-next to get v5.16-rc2.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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8626afb1 |
| 22-Nov-2021 |
Tvrtko Ursulin <tvrtko.ursulin@intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Thomas needs the dma_resv_for_each_fence API for i915/ttm async migration work.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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Revision tags: v5.15.4, v5.15.3 |
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a713ca23 |
| 18-Nov-2021 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next
Backmerging from drm/drm-next for v5.16-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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467dd91e |
| 16-Nov-2021 |
Maxime Ripard <maxime@cerno.tech> |
Merge drm/drm-fixes into drm-misc-fixes
We need -rc1 to address a breakage in drm/scheduler affecting panfrost.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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Revision tags: v5.15.2 |
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#
7f9f8792 |
| 06-Nov-2021 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
Merge remote-tracking branch 'torvalds/master' into perf/core
To pick up some tools/perf/ patches that went via tip/perf/core, such as:
tools/perf: Add mem_hops field in perf_mem_data_src structu
Merge remote-tracking branch 'torvalds/master' into perf/core
To pick up some tools/perf/ patches that went via tip/perf/core, such as:
tools/perf: Add mem_hops field in perf_mem_data_src structure
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Revision tags: v5.15.1 |
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79ef0c00 |
| 01-Nov-2021 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- kprobes: Restructured stack unwinder to show properly on x8
Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- kprobes: Restructured stack unwinder to show properly on x86 when a stack dump happens from a kretprobe callback.
- Fix to bootconfig parsing
- Have tracefs allow owner and group permissions by default (only denying others). There's been pressure to allow non root to tracefs in a controlled fashion, and using groups is probably the safest.
- Bootconfig memory managament updates.
- Bootconfig clean up to have the tools directory be less dependent on changes in the kernel tree.
- Allow perf to be traced by function tracer.
- Rewrite of function graph tracer to be a callback from the function tracer instead of having its own trampoline (this change will happen on an arch by arch basis, and currently only x86_64 implements it).
- Allow multiple direct trampolines (bpf hooks to functions) be batched together in one synchronization.
- Allow histogram triggers to add variables that can perform calculations against the event's fields.
- Use the linker to determine architecture callbacks from the ftrace trampoline to allow for proper parameter prototypes and prevent warnings from the compiler.
- Extend histogram triggers to key off of variables.
- Have trace recursion use bit magic to determine preempt context over if branches.
- Have trace recursion disable preemption as all use cases do anyway.
- Added testing for verification of tracing utilities.
- Various small clean ups and fixes.
* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits) tracing/histogram: Fix semicolon.cocci warnings tracing/histogram: Fix documentation inline emphasis warning tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together tracing: Show size of requested perf buffer bootconfig: Initialize ret in xbc_parse_tree() ftrace: do CPU checking after preemption disabled ftrace: disable preemption when recursion locked tracing/histogram: Document expression arithmetic and constants tracing/histogram: Optimize division by a power of 2 tracing/histogram: Covert expr to const if both operands are constants tracing/histogram: Simplify handling of .sym-offset in expressions tracing: Fix operator precedence for hist triggers expression tracing: Add division and multiplication support for hist triggers tracing: Add support for creating hist trigger variables from literal selftests/ftrace: Stop tracing while reading the trace file by default MAINTAINERS: Update KPROBES and TRACING entries test_kprobes: Move it from kernel/ to lib/ docs, kprobes: Remove invalid URL and add new reference samples/kretprobes: Fix return value if register_kretprobe() failed lib/bootconfig: Fix the xbc_get_info kerneldoc ...
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Revision tags: v5.15, v5.14.14, v5.14.13 |
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#
9bd98576 |
| 15-Oct-2021 |
Daniel Bristot de Oliveira <bristot@kernel.org> |
trace/osnoise: Fix an ifdef comment
s/CONFIG_OSNOISE_TRAECR/CONFIG_OSNOISE_TRACER/
No functional changes.
Link: https://lkml.kernel.org/r/33924a16f6e5559ce24952ca7d62561604bfd94a.1634308385.git.br
trace/osnoise: Fix an ifdef comment
s/CONFIG_OSNOISE_TRAECR/CONFIG_OSNOISE_TRACER/
No functional changes.
Link: https://lkml.kernel.org/r/33924a16f6e5559ce24952ca7d62561604bfd94a.1634308385.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Revision tags: v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62 |
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71af75b6 |
| 30-Aug-2021 |
Petr Mladek <pmladek@suse.com> |
Merge branch 'for-5.15-printk-index' into for-linus
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Revision tags: v5.14, v5.10.61 |
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46466ae3 |
| 26-Aug-2021 |
Ingo Molnar <mingo@kernel.org> |
Merge branch 'perf/urgent' into perf/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Revision tags: v5.10.60 |
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c87866ed |
| 17-Aug-2021 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v5.14-rc6' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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ca31fef1 |
| 27-Jul-2021 |
Maarten Lankhorst <maarten.lankhorst@linux.intel.com> |
Backmerge remote-tracking branch 'drm/drm-next' into drm-misc-next
Required bump from v5.13-rc3 to v5.14-rc3, and to pick up sysfb compilation fixes.
Signed-off-by: Maarten Lankhorst <maarten.lankh
Backmerge remote-tracking branch 'drm/drm-next' into drm-misc-next
Required bump from v5.13-rc3 to v5.14-rc3, and to pick up sysfb compilation fixes.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
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353b7a55 |
| 27-Jul-2021 |
Tony Lindgren <tony@atomide.com> |
Merge branch 'fixes-v5.14' into fixes
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Revision tags: v5.10.53, v5.10.52, v5.10.51, v5.10.50 |
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611ac726 |
| 13-Jul-2021 |
Rodrigo Vivi <rodrigo.vivi@intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Catching up with 5.14-rc1 and also preparing for a needed common topic branch for the "Minor revid/stepping and workaround cleanup"
Reference: https://patc
Merge drm/drm-next into drm-intel-gt-next
Catching up with 5.14-rc1 and also preparing for a needed common topic branch for the "Minor revid/stepping and workaround cleanup"
Reference: https://patchwork.freedesktop.org/series/92299/ Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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#
d5bfbad2 |
| 13-Jul-2021 |
Rodrigo Vivi <rodrigo.vivi@intel.com> |
Merge drm/drm-next into drm-intel-next
Catching up with 5.14-rc1
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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Revision tags: v5.10.49 |
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#
757fa80f |
| 03-Jul-2021 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Added option for per CPU threads to the hwlat tracer
- Ha
Merge tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Added option for per CPU threads to the hwlat tracer
- Have hwlat tracer handle hotplug CPUs
- New tracer: osnoise, that detects latency caused by interrupts, softirqs and scheduling of other tasks.
- Added timerlat tracer that creates a thread and measures in detail what sources of latency it has for wake ups.
- Removed the "success" field of the sched_wakeup trace event. This has been hardcoded as "1" since 2015, no tooling should be looking at it now. If one exists, we can revert this commit, fix that tool and try to remove it again in the future.
- tgid mapping fixed to handle more than PID_MAX_DEFAULT pids/tgids.
- New boot command line option "tp_printk_stop", as tp_printk causes trace events to write to console. When user space starts, this can easily live lock the system. Having a boot option to stop just after boot up is useful to prevent that from happening.
- Have ftrace_dump_on_oops boot command line option take numbers that match the numbers shown in /proc/sys/kernel/ftrace_dump_on_oops.
- Bootconfig clean ups, fixes and enhancements.
- New ktest script that tests bootconfig options.
- Add tracepoint_probe_register_may_exist() to register a tracepoint without triggering a WARN*() if it already exists. BPF has a path from user space that can do this. All other paths are considered a bug.
- Small clean ups and fixes
* tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (49 commits) tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT tracing: Simplify & fix saved_tgids logic treewide: Add missing semicolons to __assign_str uses tracing: Change variable type as bool for clean-up trace/timerlat: Fix indentation on timerlat_main() trace/osnoise: Make 'noise' variable s64 in run_osnoise() tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing tracing: Fix spelling in osnoise tracer "interferences" -> "interference" Documentation: Fix a typo on trace/osnoise-tracer trace/osnoise: Fix return value on osnoise_init_hotplug_support trace/osnoise: Make interval u64 on osnoise_main trace/osnoise: Fix 'no previous prototype' warnings tracing: Have osnoise_main() add a quiescent state for task rcu seq_buf: Make trace_seq_putmem_hex() support data longer than 8 seq_buf: Fix overflow in seq_buf_putmem_hex() trace/osnoise: Support hotplug operations trace/hwlat: Support hotplug operations trace/hwlat: Protect kdata->kthread with get/put_online_cpus trace: Add timerlat tracer trace: Add osnoise tracer ...
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#
f7d9f637 |
| 28-Jun-2021 |
Daniel Bristot de Oliveira <bristot@redhat.com> |
trace/osnoise: Fix 'no previous prototype' warnings
kernel test robot reported some osnoise functions with "no previous prototype."
Fix these warnings by making local functions static, and by addin
trace/osnoise: Fix 'no previous prototype' warnings
kernel test robot reported some osnoise functions with "no previous prototype."
Fix these warnings by making local functions static, and by adding:
void osnoise_trace_irq_entry(int id); void osnoise_trace_irq_exit(int id, const char *desc);
to include/linux/trace.h.
Link: https://lkml.kernel.org/r/e40d3cb4be8bde921f4b40fa6a095cf85ab807bd.1624872608.git.bristot@redhat.com
Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Revision tags: v5.13, v5.10.46 |
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#
bce29ac9 |
| 22-Jun-2021 |
Daniel Bristot de Oliveira <bristot@redhat.com> |
trace: Add osnoise tracer
In the context of high-performance computing (HPC), the Operating System Noise (*osnoise*) refers to the interference experienced by an application due to activities inside
trace: Add osnoise tracer
In the context of high-performance computing (HPC), the Operating System Noise (*osnoise*) refers to the interference experienced by an application due to activities inside the operating system. In the context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread can cause noise to the system. Moreover, hardware-related jobs can also cause noise, for example, via SMIs.
The osnoise tracer leverages the hwlat_detector by running a similar loop with preemption, SoftIRQs and IRQs enabled, thus allowing all the sources of *osnoise* during its execution. Using the same approach of hwlat, osnoise takes note of the entry and exit point of any source of interferences, increasing a per-cpu interference counter. The osnoise tracer also saves an interference counter for each source of interference. The interference counter for NMI, IRQs, SoftIRQs, and threads is increased anytime the tool observes these interferences' entry events. When a noise happens without any interference from the operating system level, the hardware noise counter increases, pointing to a hardware-related noise. In this way, osnoise can account for any source of interference. At the end of the period, the osnoise tracer prints the sum of all noise, the max single noise, the percentage of CPU available for the thread, and the counters for the noise sources.
Usage
Write the ASCII text "osnoise" into the current_tracer file of the tracing system (generally mounted at /sys/kernel/tracing).
For example::
[root@f32 ~]# cd /sys/kernel/tracing/ [root@f32 tracing]# echo osnoise > current_tracer
It is possible to follow the trace by reading the trace trace file::
[root@f32 tracing]# cat trace # tracer: osnoise # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth MAX # || / SINGLE Interference counters: # |||| RUNTIME NOISE % OF CPU NOISE +-----------------------------+ # TASK-PID CPU# |||| TIMESTAMP IN US IN US AVAILABLE IN US HW NMI IRQ SIRQ THREAD # | | | |||| | | | | | | | | | | <...>-859 [000] .... 81.637220: 1000000 190 99.98100 9 18 0 1007 18 1 <...>-860 [001] .... 81.638154: 1000000 656 99.93440 74 23 0 1006 16 3 <...>-861 [002] .... 81.638193: 1000000 5675 99.43250 202 6 0 1013 25 21 <...>-862 [003] .... 81.638242: 1000000 125 99.98750 45 1 0 1011 23 0 <...>-863 [004] .... 81.638260: 1000000 1721 99.82790 168 7 0 1002 49 41 <...>-864 [005] .... 81.638286: 1000000 263 99.97370 57 6 0 1006 26 2 <...>-865 [006] .... 81.638302: 1000000 109 99.98910 21 3 0 1006 18 1 <...>-866 [007] .... 81.638326: 1000000 7816 99.21840 107 8 0 1016 39 19
In addition to the regular trace fields (from TASK-PID to TIMESTAMP), the tracer prints a message at the end of each period for each CPU that is running an osnoise/CPU thread. The osnoise specific fields report:
- The RUNTIME IN USE reports the amount of time in microseconds that the osnoise thread kept looping reading the time. - The NOISE IN US reports the sum of noise in microseconds observed by the osnoise tracer during the associated runtime. - The % OF CPU AVAILABLE reports the percentage of CPU available for the osnoise thread during the runtime window. - The MAX SINGLE NOISE IN US reports the maximum single noise observed during the runtime window. - The Interference counters display how many each of the respective interference happened during the runtime window.
Note that the example above shows a high number of HW noise samples. The reason being is that this sample was taken on a virtual machine, and the host interference is detected as a hardware interference.
Tracer options
The tracer has a set of options inside the osnoise directory, they are:
- osnoise/cpus: CPUs at which a osnoise thread will execute. - osnoise/period_us: the period of the osnoise thread. - osnoise/runtime_us: how long an osnoise thread will look for noise. - osnoise/stop_tracing_us: stop the system tracing if a single noise higher than the configured value happens. Writing 0 disables this option. - osnoise/stop_tracing_total_us: stop the system tracing if total noise higher than the configured value happens. Writing 0 disables this option. - tracing_threshold: the minimum delta between two time() reads to be considered as noise, in us. When set to 0, the default value will be used, which is currently 5 us.
Additional Tracing
In addition to the tracer, a set of tracepoints were added to facilitate the identification of the osnoise source.
- osnoise:sample_threshold: printed anytime a noise is higher than the configurable tolerance_ns. - osnoise:nmi_noise: noise from NMI, including the duration. - osnoise:irq_noise: noise from an IRQ, including the duration. - osnoise:softirq_noise: noise from a SoftIRQ, including the duration. - osnoise:thread_noise: noise from a thread, including the duration.
Note that all the values are *net values*. For example, if while osnoise is running, another thread preempts the osnoise thread, it will start a thread_noise duration at the start. Then, an IRQ takes place, preempting the thread_noise, starting a irq_noise. When the IRQ ends its execution, it will compute its duration, and this duration will be subtracted from the thread_noise, in such a way as to avoid the double accounting of the IRQ execution. This logic is valid for all sources of noise.
Here is one example of the usage of these tracepoints::
osnoise/8-961 [008] d.h. 5789.857532: irq_noise: local_timer:236 start 5789.857529929 duration 1845 ns osnoise/8-961 [008] dNh. 5789.858408: irq_noise: local_timer:236 start 5789.858404871 duration 2848 ns migration/8-54 [008] d... 5789.858413: thread_noise: migration/8:54 start 5789.858409300 duration 3068 ns osnoise/8-961 [008] .... 5789.858413: sample_threshold: start 5789.858404555 duration 8723 ns interferences 2
In this example, a noise sample of 8 microseconds was reported in the last line, pointing to two interferences. Looking backward in the trace, the two previous entries were about the migration thread running after a timer IRQ execution. The first event is not part of the noise because it took place one millisecond before.
It is worth noticing that the sum of the duration reported in the tracepoints is smaller than eight us reported in the sample_threshold. The reason roots in the overhead of the entry and exit code that happens before and after any interference execution. This justifies the dual approach: measuring thread and tracing.
Link: https://lkml.kernel.org/r/e649467042d60e7b62714c9c6751a56299d15119.1624372313.git.bristot@redhat.com
Cc: Phil Auld <pauld@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Kate Carcia <kcarcia@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Alexandre Chartre <alexandre.chartre@oracle.com> Cc: Clark Willaims <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> [ Made the following functions static: trace_irqentry_callback() trace_irqexit_callback() trace_intel_irqentry_callback() trace_intel_irqexit_callback()
Added to include/trace.h: osnoise_arch_register() osnoise_arch_unregister()
Fixed define logic for LATENCY_FS_NOTIFY
Reported-by: kernel test robot <lkp@intel.com> ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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