History log of /openbmc/linux/kernel/trace/trace_entries.h (Results 1 – 25 of 472)
Revision (<<< Hide revision tags) (Show revision tags >>>) Date Author Comments
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
# c900529f 12-Sep-2023 Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-fixes into drm-misc-fixes

Forwarding to v6.6-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>


Revision tags: v6.5.2, v6.1.51, v6.5.1
# 34232fcf 01-Sep-2023 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
"User visible changes:

- Added a way to easier filter with cp

Merge tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
"User visible changes:

- Added a way to easier filter with cpumasks:

# echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter

- Show actual size of ring buffer after modifying the ring buffer
size via buffer_size_kb.

Currently it just returns what was written, but the actual size
rounds up to the sub buffer size. Show that real size instead.

Major changes:

- Added "eventfs". This is the code that handles the inodes and
dentries of tracefs/events directory. As there are thousands of
events, and each event has several inodes and dentries that
currently exist even when tracing is never used, they take up
precious memory. Instead, eventfs will allocate the inodes and
dentries in a JIT way (similar to what procfs does). There is now
metadata that handles the events and subdirectories, and will
create the inodes and dentries when they are used.

Note, I also have patches that remove the subdirectory meta data,
but will wait till the next merge window before applying them. It's
a little more complex, and I want to make sure the dynamic code
works properly before adding more complexity, making it easier to
revert if need be.

Minor changes:

- Optimization to user event list traversal

- Remove intermediate permission of tracefs files (note the
intermediate permission removes all access to the files so it is
not a security concern, but just a clean up)

- Add the complex fix to FORTIFY_SOURCE to the kernel stack event
logic

- Other minor cleanups"

* tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits)
tracefs: Remove kerneldoc from struct eventfs_file
tracefs: Avoid changing i_mode to a temp value
tracing/user_events: Optimize safe list traversals
ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon()
tracing: Remove unused function declarations
tracing/filters: Document cpumask filtering
tracing/filters: Further optimise scalar vs cpumask comparison
tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU
tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU
tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU
tracing/filters: Enable filtering the CPU common field by a cpumask
tracing/filters: Enable filtering a scalar field by a cpumask
tracing/filters: Enable filtering a cpumask field by another cpumask
tracing/filters: Dynamically allocate filter_pred.regex
test: ftrace: Fix kprobe test for eventfs
eventfs: Move tracing/events to eventfs
eventfs: Implement removal of meta data from eventfs
eventfs: Implement functions to create files and dirs when accessed
eventfs: Implement eventfs lookup, read, open functions
eventfs: Implement eventfs file add functions
...

show more ...


Revision tags: v6.1.50, v6.5, v6.1.49, v6.1.48, v6.1.46, v6.1.45, v6.1.44
# 2612e3bb 07-Aug-2023 Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo V

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

show more ...


# 9f771739 07-Aug-2023 Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/1

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/121735/

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...


Revision tags: v6.1.43, v6.1.42, v6.1.41, v6.1.40, v6.1.39
# e7186af7 13-Jul-2023 Steven Rostedt (Google) <rostedt@goodmis.org>

tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure

For backward compatibility, older tooling expects to see the kernel_stack
event with a "caller" field that is a fixed size arra

tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure

For backward compatibility, older tooling expects to see the kernel_stack
event with a "caller" field that is a fixed size array of 8 addresses. The
code now supports more than 8 with an added "size" field that states the
real number of entries. But the "caller" field still just looks like a
fixed size to user space.

Since the tracing macros that create the user space format files also
creates the structures that those files represent, the kernel_stack event
structure had its "caller" field a fixed size of 8, but in reality, when
it is allocated on the ring buffer, it can hold more if the stack trace is
bigger that 8 functions. The copying of these entries was simply done with
a memcpy():

size = nr_entries * sizeof(unsigned long);
memcpy(entry->caller, fstack->calls, size);

The FORTIFY_SOURCE logic noticed at runtime that when the nr_entries was
larger than 8, that the memcpy() was writing more than what the structure
stated it can hold and it complained about it. This is because the
FORTIFY_SOURCE code is unaware that the amount allocated is actually
enough to hold the size. It does not expect that a fixed size field will
hold more than the fixed size.

This was originally solved by hiding the caller assignment with some
pointer arithmetic.

ptr = ring_buffer_data();
entry = ptr;

ptr += offsetof(typeof(*entry), caller);
memcpy(ptr, fstack->calls, size);

But it is considered bad form to hide from kernel hardening. Instead, make
it work nicely with FORTIFY_SOURCE by adding a new __stack_array() macro
that is specific for this one special use case. The macro will take 4
arguments: type, item, len, field (whereas the __array() macro takes just
the first three). This macro will act just like the __array() macro when
creating the code to deal with the format file that is exposed to user
space. But for the kernel, it will turn the caller field into:

type item[] __counted_by(field);

or for this instance:

unsigned long caller[] __counted_by(size);

Now the kernel code can expose the assignment of the caller to the
FORTIFY_SOURCE and everyone is happy!

Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20230713092605.2ddb9788@rorschach.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

show more ...


# 61b73694 24-Jul-2023 Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-misc-next

Backmerging to get v6.5-rc2.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>


# 0791faeb 17-Jul-2023 Mark Brown <broonie@kernel.org>

ASoC: Merge v6.5-rc2

Get a similar baseline to my other branches, and fixes for people using
the branch.


# 2f98e686 11-Jul-2023 Maxime Ripard <mripard@kernel.org>

Merge v6.5-rc1 into drm-misc-fixes

Boris needs 6.5-rc1 in drm-misc-fixes to prevent a conflict.

Signed-off-by: Maxime Ripard <mripard@kernel.org>


Revision tags: v6.1.38
# 3fbff91a 02-Jul-2023 Andrew Morton <akpm@linux-foundation.org>

Merge branch 'master' into mm-hotfixes-stable


Revision tags: v6.1.37
# cccf0c2e 30-Jun-2023 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

- Add new feature to have function graph tracer record the retur

Merge tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

- Add new feature to have function graph tracer record the return
value. Adds a new option: funcgraph-retval ; when set, will show the
return value of a function in the function graph tracer.

- Also add the option: funcgraph-retval-hex where if it is not set, and
the return value is an error code, then it will return the decimal of
the error code, otherwise it still reports the hex value.

- Add the file /sys/kernel/tracing/osnoise/per_cpu/cpu<cpu>/timerlat_fd
That when a application opens it, it becomes the task that the timer
lat tracer traces. The application can also read this file to find
out how it's being interrupted.

- Add the file /sys/kernel/tracing/available_filter_functions_addrs
that works just the same as available_filter_functions but also shows
the addresses of the functions like kallsyms, except that it gives
the address of where the fentry/mcount jump/nop is. This is used by
BPF to make it easier to attach BPF programs to ftrace hooks.

- Replace strlcpy with strscpy in the tracing boot code.

* tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix warnings when building htmldocs for function graph retval
riscv: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
tracing/boot: Replace strlcpy with strscpy
tracing/timerlat: Add user-space interface
tracing/osnoise: Skip running osnoise if all instances are off
tracing/osnoise: Switch from PF_NO_SETAFFINITY to migrate_disable
ftrace: Show all functions with addresses in available_filter_functions_addrs
selftests/ftrace: Add funcgraph-retval test case
LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
tracing: Add documentation for funcgraph-retval and funcgraph-retval-hex
function_graph: Support recording and printing the return value of function
fgraph: Add declaration of "struct fgraph_ret_regs"

show more ...


Revision tags: 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
# a1be9ccc 08-Apr-2023 Donglin Peng <pengdonglin@sangfor.com.cn>

function_graph: Support recording and printing the return value of function

Analyzing system call failures with the function_graph tracer can be a
time-consuming process, particularly when locating

function_graph: Support recording and printing the return value of function

Analyzing system call failures with the function_graph tracer can be a
time-consuming process, particularly when locating the kernel function
that first returns an error in the trace logs. This change aims to
simplify the process by recording the function return value to the
'retval' member of 'ftrace_graph_ret' and printing it when outputting
the trace log.

We have introduced new trace options: funcgraph-retval and
funcgraph-retval-hex. The former controls whether to display the return
value, while the latter controls the display format.

Please note that even if a function's return type is void, a return
value will still be printed. You can simply ignore it.

This patch only establishes the fundamental infrastructure. Subsequent
patches will make this feature available on some commonly used processor
architectures.

Here is an example:

I attempted to attach the demo process to a cpu cgroup, but it failed:

echo `pidof demo` > /sys/fs/cgroup/cpu/test/tasks
-bash: echo: write error: Invalid argument

The strace logs indicate that the write system call returned -EINVAL(-22):
...
write(1, "273\n", 4) = -1 EINVAL (Invalid argument)
...

To capture trace logs during a write system call, use the following
commands:

cd /sys/kernel/debug/tracing/
echo 0 > tracing_on
echo > trace
echo *sys_write > set_graph_function
echo *spin* > set_graph_notrace
echo *rcu* >> set_graph_notrace
echo *alloc* >> set_graph_notrace
echo preempt* >> set_graph_notrace
echo kfree* >> set_graph_notrace
echo $$ > set_ftrace_pid
echo function_graph > current_tracer
echo 1 > options/funcgraph-retval
echo 0 > options/funcgraph-retval-hex
echo 1 > tracing_on
echo `pidof demo` > /sys/fs/cgroup/cpu/test/tasks
echo 0 > tracing_on
cat trace > ~/trace.log

To locate the root cause, search for error code -22 directly in the file
trace.log and identify the first function that returned -22. Once you
have identified this function, examine its code to determine the root
cause.

For example, in the trace log below, cpu_cgroup_can_attach
returned -22 first, so we can focus our analysis on this function to
identify the root cause.

...

1) | cgroup_migrate() {
1) 0.651 us | cgroup_migrate_add_task(); /* = 0xffff93fcfd346c00 */
1) | cgroup_migrate_execute() {
1) | cpu_cgroup_can_attach() {
1) | cgroup_taskset_first() {
1) 0.732 us | cgroup_taskset_next(); /* = 0xffff93fc8fb20000 */
1) 1.232 us | } /* cgroup_taskset_first = 0xffff93fc8fb20000 */
1) 0.380 us | sched_rt_can_attach(); /* = 0x0 */
1) 2.335 us | } /* cpu_cgroup_can_attach = -22 */
1) 4.369 us | } /* cgroup_migrate_execute = -22 */
1) 7.143 us | } /* cgroup_migrate = -22 */

...

Link: https://lkml.kernel.org/r/1fc502712c981e0e6742185ba242992170ac9da8.1680954589.git.pengdonglin@sangfor.com.cn

Tested-by: Florian Kauer <florian.kauer@linutronix.de>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

show more ...


Revision tags: 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, 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, 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, v5.15.15
# 762f99f4 15-Jan-2022 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge branch 'next' into for-linus

Prepare input updates for 5.17 merge window.


Revision tags: v5.16, v5.15.10, v5.15.9, v5.15.8
# 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.


Revision tags: v5.15.7, v5.15.6, v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, 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
# 8be98d2f 05-Sep-2021 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge branch 'next' into for-linus

Prepare input updates for 5.15 merge window.


Revision tags: v5.14.1, v5.10.62
# 71af75b6 30-Aug-2021 Petr Mladek <pmladek@suse.com>

Merge branch 'for-5.15-printk-index' into for-linus


Revision tags: v5.14, v5.10.61
# 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>


Revision tags: v5.10.60
# 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>


# 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>

show more ...


# 353b7a55 27-Jul-2021 Tony Lindgren <tony@atomide.com>

Merge branch 'fixes-v5.14' into fixes


Revision tags: v5.10.53, v5.10.52, v5.10.51
# 320424c7 18-Jul-2021 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge tag 'v5.13' into next

Sync up with the mainline to get the latest parport API.


Revision tags: v5.10.50
# 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>

show more ...


# 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>


Revision tags: v5.10.49
# 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
...

show more ...


# 5a94296b 30-Jun-2021 Jiri Kosina <jkosina@suse.cz>

Merge branch 'for-5.14/amd-sfh' into for-linus

- support for Renoir and Cezanne SoCs
- support for Ambient Light Sensor
- support for Human Presence Detection sensor

all from Basavaraj Natikar


Revision tags: v5.13, v5.10.46
# a955d7ea 22-Jun-2021 Daniel Bristot de Oliveira <bristot@redhat.com>

trace: Add timerlat tracer

The timerlat tracer aims to help the preemptive kernel developers to
found souces of wakeup latencies of real-time threads. Like cyclictest,
the tracer sets a periodic tim

trace: Add timerlat tracer

The timerlat tracer aims to help the preemptive kernel developers to
found souces of wakeup latencies of real-time threads. Like cyclictest,
the tracer sets a periodic timer that wakes up a thread. The thread then
computes a *wakeup latency* value as the difference between the *current
time* and the *absolute time* that the timer was set to expire. The main
goal of timerlat is tracing in such a way to help kernel developers.

Usage

Write the ASCII text "timerlat" 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 timerlat > current_tracer

It is possible to follow the trace by reading the trace trace file:

[root@f32 tracing]# cat trace
# tracer: timerlat
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# || /
# |||| ACTIVATION
# TASK-PID CPU# |||| TIMESTAMP ID CONTEXT LATENCY
# | | | |||| | | | |
<idle>-0 [000] d.h1 54.029328: #1 context irq timer_latency 932 ns
<...>-867 [000] .... 54.029339: #1 context thread timer_latency 11700 ns
<idle>-0 [001] dNh1 54.029346: #1 context irq timer_latency 2833 ns
<...>-868 [001] .... 54.029353: #1 context thread timer_latency 9820 ns
<idle>-0 [000] d.h1 54.030328: #2 context irq timer_latency 769 ns
<...>-867 [000] .... 54.030330: #2 context thread timer_latency 3070 ns
<idle>-0 [001] d.h1 54.030344: #2 context irq timer_latency 935 ns
<...>-868 [001] .... 54.030347: #2 context thread timer_latency 4351 ns

The tracer creates a per-cpu kernel thread with real-time priority that
prints two lines at every activation. The first is the *timer latency*
observed at the *hardirq* context before the activation of the thread.
The second is the *timer latency* observed by the thread, which is the
same level that cyclictest reports. The ACTIVATION ID field
serves to relate the *irq* execution to its respective *thread* execution.

The irq/thread splitting is important to clarify at which context
the unexpected high value is coming from. The *irq* context can be
delayed by hardware related actions, such as SMIs, NMIs, IRQs
or by a thread masking interrupts. Once the timer happens, the delay
can also be influenced by blocking caused by threads. For example, by
postponing the scheduler execution via preempt_disable(), by the
scheduler execution, or by masking interrupts. Threads can
also be delayed by the interference from other threads and IRQs.

The timerlat can also take advantage of the osnoise: traceevents.
For example:

[root@f32 ~]# cd /sys/kernel/tracing/
[root@f32 tracing]# echo timerlat > current_tracer
[root@f32 tracing]# echo osnoise > set_event
[root@f32 tracing]# echo 25 > osnoise/stop_tracing_total_us
[root@f32 tracing]# tail -10 trace
cc1-87882 [005] d..h... 548.771078: #402268 context irq timer_latency 1585 ns
cc1-87882 [005] dNLh1.. 548.771082: irq_noise: local_timer:236 start 548.771077442 duration 4597 ns
cc1-87882 [005] dNLh2.. 548.771083: irq_noise: reschedule:253 start 548.771083017 duration 56 ns
cc1-87882 [005] dNLh2.. 548.771086: irq_noise: call_function_single:251 start 548.771083811 duration 2048 ns
cc1-87882 [005] dNLh2.. 548.771088: irq_noise: call_function_single:251 start 548.771086814 duration 1495 ns
cc1-87882 [005] dNLh2.. 548.771091: irq_noise: call_function_single:251 start 548.771089194 duration 1558 ns
cc1-87882 [005] dNLh2.. 548.771094: irq_noise: call_function_single:251 start 548.771091719 duration 1932 ns
cc1-87882 [005] dNLh2.. 548.771096: irq_noise: call_function_single:251 start 548.771094696 duration 1050 ns
cc1-87882 [005] d...3.. 548.771101: thread_noise: cc1:87882 start 548.771078243 duration 10909 ns
timerlat/5-1035 [005] ....... 548.771103: #402268 context thread timer_latency 25960 ns

For further information see: Documentation/trace/timerlat-tracer.rst

Link: https://lkml.kernel.org/r/71f18efc013e1194bcaea1e54db957de2b19ba62.1624372313.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>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

show more ...


12345678910>>...19