IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
Avoid double free by making trace_instance_destroy indempotent. When
trace_instance_init fails, it calls trace_instance_destroy, but its only
caller osnoise_destroy_tool calls it again.
Link: https://lkml.kernel.org/r/mvmilnlkyzx.fsf_-_@suse.de
Fixes: 0605bf009f ("rtla: Add osnoise tool")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Sedat Dilek reported an error on rtla Makefile when running:
$ make -C tools/ clean
[...]
make[2]: Entering directory
'/home/dileks/src/linux-kernel/git/tools/tracing/rtla'
[...]
'/home/dileks/src/linux-kernel/git/Documentation/tools/rtla'
/bin/sh: 1: test: rtla-make[2]:: unexpected operator <------ The problem
rm: cannot remove '/home/dileks/src/linux-kernel/git': Is a directory
make[2]: *** [Makefile:120: clean] Error 1
make[2]: Leaving directory
This occurred because the rtla calls kernel's Makefile to get the
version in silence mode, e.g.,
$ make -sC ../../.. kernelversion
5.19.0-rc4
But the -s is being ignored when rtla's makefile is called indirectly,
so the output looks like this:
$ make -C ../../.. kernelversion
make: Entering directory '/root/linux'
5.19.0-rc4
make: Leaving directory '/root/linux'
Using 'grep -v make' avoids this problem, e.g.,
$ make -C ../../.. kernelversion | grep -v make
5.19.0-rc4
Thus, add | grep -v make.
Link: https://lkml.kernel.org/r/870c02d4d97a921f02a31fa3b229fc549af61a20.1657747763.git.bristot@kernel.org
Fixes: 8619e32825 ("rtla: Follow kernel version")
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Daniel Wagner reported to me that readproc.h got deprecated. Also,
while the procps-ng library was available on Fedora, it was not available
on RHEL, which is a piece of evidence that it was not that used.
rtla uses procps-ng only to find the PID of the tracers' workload.
I used the procps-ng library to avoid reinventing the wheel. But in this
case, reinventing the wheel took me less time than the time we already
took trying to work around problems.
Implement a function that reads /proc/ entries, checking if:
- the entry is a directory
- the directory name is composed only of digits (PID)
- the directory contains the comm file
- the comm file contains a comm that matches the tracers'
workload prefix.
- then return true; otherwise, return false.
And use it instead of procps-ng.
Link: https://lkml.kernel.org/r/e8276e122ee9eb2c5a0ba8e673fb6488b924b825.1652423574.git.bristot@kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tao Zhou <tao.zhou@linux.dev>
Fixes: b1696371d8 ("rtla: Helper functions for rtla")
Reported-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull Kbuild updates from Masahiro Yamada:
- Add new environment variables, USERCFLAGS and USERLDFLAGS to allow
additional flags to be passed to user-space programs.
- Fix missing fflush() bugs in Kconfig and fixdep
- Fix a minor bug in the comment format of the .config file
- Make kallsyms ignore llvm's local labels, .L*
- Fix UAPI compile-test for cross-compiling with Clang
- Extend the LLVM= syntax to support LLVM=<suffix> form for using a
particular version of LLVm, and LLVM=<prefix> form for using custom
LLVM in a particular directory path.
- Clean up Makefiles
* tag 'kbuild-v5.18-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: Make $(LLVM) more flexible
kbuild: add --target to correctly cross-compile UAPI headers with Clang
fixdep: use fflush() and ferror() to ensure successful write to files
arch: syscalls: simplify uapi/kapi directory creation
usr/include: replace extra-y with always-y
certs: simplify empty certs creation in certs/Makefile
certs: include certs/signing_key.x509 unconditionally
kallsyms: ignore all local labels prefixed by '.L'
kconfig: fix missing '# end of' for empty menu
kconfig: add fflush() before ferror() check
kbuild: replace $(if A,A,B) with $(or A,B)
kbuild: Add environment variables for userprogs flags
kbuild: unify cmd_copy and cmd_shipped
Add --trigger option. This option enables a trace event trigger to the
previous -e sys:event argument, allowing some advanced tracing options.
For instance, in a system with CPUs 2:23 isolated, it is possible to get
a stack trace of thread wakeup targeting those CPUs while running
osnoise with the following command line:
# osnoise top -c 2-23 -a 50 -e sched:sched_wakeup --trigger="stacktrace if target_cpu >= 2"
This option is available for all current tools.
Link: https://lkml.kernel.org/r/07d2983d5f71261d4da89dbaf02efcad100ab8ee.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add the -a/--auto <arg in us> option. This option sets some commonly
used options while debugging the system. It aims to help users produce
reports in the field, reducing the number of arguments passed to the
tool in the first approach to a problem.
It is equivalent to setting osnoise/stop_tracing_us with the argument,
setting tracing_thresh to 1 us, and saving the trace to osnoise_trace.txt
file if the trace is stopped automatically.
Link: https://lkml.kernel.org/r/ef04c961b227eb93a83cd0b54bfca45e1a381b77.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently, --entries uses -e as the short version in the hist mode of
timerlat and osnoise tools. But as -e is already used to enable events
on trace sessions by other tools, thus let's keep it available for the
same usage for all rtla tools.
Make -E the short version of --entries for hist mode on all tools.
Note: rtla was merged in this merge window, so rtla was not released yet.
Link: https://lkml.kernel.org/r/5dbf0cbe7364d3a05e708926b41a097c59a02b1e.1645206561.git.bristot@kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
$(or ...) is available since GNU Make 3.81, and useful to shorten the
code in some places.
Covert as follows:
$(if A,A,B) --> $(or A,B)
This patch also converts:
$(if A, A, B) --> $(or A, B)
Strictly speaking, the latter is not an equivalent conversion because
GNU Make keeps spaces after commas; if A is not empty, $(if A, A, B)
expands to " A", while $(or A, B) expands to "A".
Anyway, preceding spaces are not significant in the code hunks I touched.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
rtla osnoise and timerlat are causing a segmentation fault when running
with the --trace option on a kernel that does not support multiple
instances. For example:
[root@f34 rtla]# rtla osnoise top -t
failed to enable the tracer osnoise
Could not enable osnoiser tracer for tracing
Failed to enable the trace instance
Segmentation fault (core dumped)
This error happens because the exit code of the tools is trying
to destroy the trace instance that failed to be created.
Make osnoise_destroy_tool() aware of possible NULL osnoise_tool *,
and do not attempt to destroy it. This also simplifies the exit code.
Link: https://lkml.kernel.org/r/5660a2b6bf66c2655842360f2d7f6b48db5dba23.1644327249.git.bristot@kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 1eceb2fc2c ("rtla/osnoise: Add osnoise top mode")
Fixes: 829a6c0b56 ("rtla/osnoise: Add the hist mode")
Fixes: a828cd18bc ("rtla: Add timerlat tool and timelart top mode")
Fixes: 1eeb6328e8 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The rtla timerlat tool is an interface for the timerlat tracer.
The timerlat tracer dispatches a kernel thread per-cpu. These threads set a
periodic timer to wake themselves up and go back to sleep. After the
wakeup, they collect and generate useful information for the debugging of
operating system timer latency.
The timerlat tracer outputs information in two ways. It periodically
prints the timer latency at the timer IRQ handler and the Thread handler.
It also provides information for each noise via the osnoise tracepoints.
The rtla timerlat top mode displays a summary of the periodic output from
the timerlat tracer.
Here is one example of the rtla timerlat tool output:
---------- %< ----------
[root@alien ~]# rtla timerlat top -c 0-3 -d 1m
Timer Latency
0 00:01:00 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
0 #60001 | 0 0 0 3 | 1 1 1 6
1 #60001 | 0 0 0 3 | 2 1 1 5
2 #60001 | 0 0 1 6 | 1 1 2 7
3 #60001 | 0 0 0 7 | 1 1 1 11
---------- >% ----------
Running:
# rtla timerlat --help
# rtla timerlat top --help
provides information about the available options.
Link: https://lkml.kernel.org/r/e95032e20c2b88c962195bf7693bb53c9ebcced8.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The rtla osnoise tool is an interface for the osnoise tracer. The
osnoise tracer dispatches a kernel thread per-cpu. These threads read
the time in a loop while with preemption, softirqs and IRQs enabled,
thus allowing all the sources of osnoise during its execution. The
osnoise threads take 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 rtla osnoise top mode displays information about the periodic
summary from the osnoise tracer.
One example of rtla osnoise top output is:
[root@alien ~]# rtla osnoise top -c 0-3 -d 1m -q -r 900000 -P F:1
Operating System Noise
duration: 0 00:01:00 | time is in us
CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI IRQ Softirq Thread
0 #58 52200000 1031 99.99802 91 60 0 0 52285 0 101
1 #59 53100000 5 99.99999 5 5 0 9 53122 0 18
2 #59 53100000 7 99.99998 7 7 0 8 53115 0 18
3 #59 53100000 8274 99.98441 277 23 0 9 53778 0 660
"rtla osnoise top --help" works and provide information about the
available options.
Link: https://lkml.kernel.org/r/0d796993abf587ae5a170bb8415c49368d4999e1.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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>
