| #
9b838a3c |
| 02-Mar-2021 |
Takashi Iwai <tiwai@suse.de> |
Merge tag 'tags/sound-sdw-kconfig-fixes' into for-linus
ALSA/ASoC/SOF/SoundWire: fix Kconfig issues
In January, Intel kbuild bot and Arnd Bergmann reported multiple
issues with randconfig. This pat
Merge tag 'tags/sound-sdw-kconfig-fixes' into for-linus
ALSA/ASoC/SOF/SoundWire: fix Kconfig issues
In January, Intel kbuild bot and Arnd Bergmann reported multiple
issues with randconfig. This patchset builds on Arnd's suggestions to
a) expose ACPI and PCI devices in separate modules, while sof-acpi-dev
and sof-pci-dev become helpers. This will result in minor changes
required for developers/testers, i.e. modprobe snd-sof-pci will no
longer result in a probe. The SOF CI was already updated to deal with
this module dependency change and introduction of new modules.
b) Fix SOF/SoundWire/DSP_config dependencies by moving the code
required to detect SoundWire presence in ACPI tables to sound/hda.
Link: https://lore.kernel.org/r/20210302003125.1178419-1-pierre-louis.bossart@linux.intel.com
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| #
c9584234 |
| 22-Feb-2021 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'trace-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Update to the way irqs and preemption is tracked via the tr
Merge tag 'trace-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Update to the way irqs and preemption is tracked via the trace event
PC field
- Fix handling of unregistering event failing due to allocate memory.
This is only triggered by failure injection, as it is pretty much
guaranteed to have less than a page allocation succeed.
- Do not show the useless "filter" or "enable" files for the "ftrace"
trace system, as they have no effect on doing anything.
- Add a warning if kprobes are registered more than once.
- Synthetic events now have their fields parsed by semicolons. Old
formats without semicolons will still work, but new features will
require them.
- New option to allow trace events to show %p without hashing in trace
file. The trace file can only be read by root, and reading the raw
event buffer did not have any pointers hashed, so this does not
expose anything new.
- New directory in tools called tools/tracing, where a new tool that
reads sequential latency reports from the ftrace latency tracers.
- Other minor fixes and cleanups.
* tag 'trace-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
kprobes: Fix to delay the kprobes jump optimization
tracing/tools: Add the latency-collector to tools directory
tracing: Make hash-ptr option default
tracing: Add ptr-hash option to show the hashed pointer value
tracing: Update the stage 3 of trace event macro comment
tracing: Show real address for trace event arguments
selftests/ftrace: Add '!event' synthetic event syntax check
selftests/ftrace: Update synthetic event syntax errors
tracing: Add a backward-compatibility check for synthetic event creation
tracing: Update synth command errors
tracing: Rework synthetic event command parsing
tracing/dynevent: Delegate parsing to create function
kprobes: Warn if the kprobe is reregistered
ftrace: Remove unused ftrace_force_update()
tracepoints: Code clean up
tracepoints: Do not punish non static call users
tracepoints: Remove unnecessary "data_args" macro parameter
tracing: Do not create "enable" or "filter" files for ftrace event subsystem
kernel: trace: preemptirq_delay_test: add cpu affinity
tracepoint: Do not fail unregistering a probe due to memory failure
...
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| #
e23db805 |
| 12-Feb-2021 |
Viktor Rosendahl <Viktor.Rosendahl@bmw.de> |
tracing/tools: Add the latency-collector to tools directory
This is a tool that is intended to work around the fact that the
preemptoff, irqsoff, and preemptirqsoff tracers only work in
overwrite mo
tracing/tools: Add the latency-collector to tools directory
This is a tool that is intended to work around the fact that the
preemptoff, irqsoff, and preemptirqsoff tracers only work in
overwrite mode. The idea is to act randomly in such a way that we
do not systematically lose any latencies, so that if enough testing
is done, all latencies will be captured. If the same burst of
latencies is repeated, then sooner or later we will have captured all
the latencies.
It also works with the wakeup_dl, wakeup_rt, and wakeup tracers.
However, in that case it is probably not useful to use the random
sleep functionality.
The reason why it may be desirable to catch all latencies with a long
test campaign is that for some organizations, it's necessary to test
the kernel in the field and not practical for developers to work
iteratively with field testers. Because of cost and project schedules
it is not possible to start a new test campaign every time a latency
problem has been fixed.
It uses inotify to detect changes to /sys/kernel/tracing/trace.
When a latency is detected, it will either sleep or print
immediately, depending on a function that act as an unfair coin
toss.
If immediate print is chosen, it means that we open
/sys/kernel/tracing/trace and thereby cause a blackout period
that will hide any subsequent latencies.
If sleep is chosen, it means that we wait before opening
/sys/kernel/tracing/trace, by default for 1000 ms, to see if
there is another latency during this period. If there is, then we will
lose the previous latency. The coin will be tossed again with a
different probability, and we will either print the new latency, or
possibly a subsequent one.
The probability for the unfair coin toss is chosen so that there
is equal probability to obtain any of the latencies in a burst.
However, this assumes that we make an assumption of how many
latencies there can be. By default the program assumes that there
are no more than 2 latencies in a burst, the probability of immediate
printout will be:
1/2 and 1
Thus, the probability of getting each of the two latencies will be 1/2.
If we ever find that there is more than one latency in a series,
meaning that we reach the probability of 1, then the table will be
expanded to:
1/3, 1/2, and 1
Thus, we assume that there are no more than three latencies and each
with a probability of 1/3 of being captured. If the probability of 1
is reached in the new table, that is we see more than two closely
occurring latencies, then the table will again be extended, and so
on.
On my systems, it seems like this scheme works fairly well, as
long as the latencies we trace are long enough, 300 us seems to be
enough. This userspace program receive the inotify event at the end
of a latency, and it has time until the end of the next latency
to react, that is to open /sys/kernel/tracing/trace. Thus,
if we trace latencies that are >300 us, then we have at least 300 us
to react.
The minimum latency will of course not be 300 us on all systems, it
will depend on the hardware, kernel version, workload and
configuration.
Example usage:
In one shell, give the following command:
sudo latency-collector -rvv -t preemptirqsoff -s 2000 -a 3
This will trace latencies > 2000us with the preemptirqsoff tracer,
using random sleep with maximum verbosity, with a probability
table initialized to a size of 3.
In another shell, generate a few bursts of latencies:
root@host:~# modprobe preemptirq_delay_test delay=3000 test_mode=alternate
burst_size=3
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
If all goes well, you should be getting stack traces that shows
all the different latencies, i.e. you should see all the three
functions preemptirqtest_0, preemptirqtest_1, preemptirqtest_2 in the
stack traces.
Link: https://lkml.kernel.org/r/20210212134421.172750-2-Viktor.Rosendahl@bmw.de
Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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