linux-stable.git/tools/tracing, branch v6.9.2 Linux kernel stable tree tools/rtla: Add -U/--user-load option to timerlat 2024-03-20T04:39:06+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-02-06T14:32:06+00:00 a23c05fd76cf4ad27e0c74f7a93e7b089e94a55c The timerlat tracer provides an interface for any application to wait for the timerlat's periodic wakeup. Currently, rtla timerlat uses it to dispatch its user-space workload (-u option). But as the tracer interface is generic, rtla timerlat can also be used to monitor any workload that uses it. For example, a user might place their own workload to wait on the tracer interface, and monitor the results with rtla timerlat. Add the -U option to rtla timerlat top and hist. With this option, rtla timerlat will not dispatch its workload but only setting up the system, waiting for a user to dispatch its workload. The sample code in this patch is an example of python application that loops in the timerlat tracer fd. To use it, dispatch: # rtla timerlat -U In a terminal, then run the python program on another terminal, specifying the CPU to run it. For example, setting on CPU 1: #./timerlat_load.py 1 Then rtla timerlat will start printing the statistics of the ./timerlat_load.py app. An interesting point is that the "Ret user Timer Latency" value is the overall response time of the load. The sample load does a memory copy to exemplify that. The stop tracing options on rtla timerlat works in this setup as well, including auto analysis. Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispatch its user-space workload (-u option).

But as the tracer interface is generic, rtla timerlat can also be used
to monitor any workload that uses it. For example, a user might
place their own workload to wait on the tracer interface, and
monitor the results with rtla timerlat.

Add the -U option to rtla timerlat top and hist. With this option, rtla
timerlat will not dispatch its workload but only setting up the
system, waiting for a user to dispatch its workload.

The sample code in this patch is an example of python application
that loops in the timerlat tracer fd.

To use it, dispatch:

 # rtla timerlat -U

In a terminal, then run the python program on another terminal,
specifying the CPU to run it. For example, setting on CPU 1:

 #./timerlat_load.py 1

Then rtla timerlat will start printing the statistics of the
./timerlat_load.py app.

An interesting point is that the "Ret user Timer Latency" value
is the overall response time of the load. The sample load does
a memory copy to exemplify that.

The stop tracing options on rtla timerlat works in this setup
as well, including auto analysis.

Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Use tools/build makefiles to build rtla 2024-03-20T04:39:06+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-03-15T16:44:04+00:00 01474dc706cabbdaab600a46a107220ac5de9386 Use tools/build/ makefiles to build rtla, inheriting the benefits of it. For example, having a proper way to handle dependencies. rtla is built using perf infra-structure when building inside the kernel tree. At this point, rtla diverges from perf in two points: Documentation and tarball generation/build. At the documentation level, rtla is one step ahead, placing the documentation at Documentation/tools/rtla/, using the same build tools as kernel documentation. The idea is to move perf documentation to the same scheme and then share the same makefiles. rtla has a tarball target that the (old) RHEL8 uses. The tarball was kept using a simple standalone makefile for compatibility. The standalone makefile shares most of the code, e.g., flags, with regular buildings. The tarball method was set as deprecated. If necessary, we can make a rtla tarball like perf, which includes the entire tools/build. But this would also require changes in the user side (the directory structure changes, and probably the deps to build the package). Inspired on perf and objtool. Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Use tools/build/ makefiles to build rtla, inheriting the benefits of
it. For example, having a proper way to handle dependencies.

rtla is built using perf infra-structure when building inside the
kernel tree.

At this point, rtla diverges from perf in two points: Documentation
and tarball generation/build.

At the documentation level, rtla is one step ahead, placing the
documentation at Documentation/tools/rtla/, using the same build
tools as kernel documentation. The idea is to move perf
documentation to the same scheme and then share the same makefiles.

rtla has a tarball target that the (old) RHEL8 uses. The tarball was
kept using a simple standalone makefile for compatibility. The
standalone makefile shares most of the code, e.g., flags, with
regular buildings.

The tarball method was set as deprecated. If necessary, we can make
a rtla tarball like perf, which includes the entire tools/build.
But this would also require changes in the user side (the directory
structure changes, and probably the deps to build the package).

Inspired on perf and objtool.

Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/tracing: Use tools/build makefiles on latency-collector 2024-03-20T04:39:06+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-03-15T16:44:03+00:00 9d56c88e522517652213e9622dcae159e6372fd3 Use tools/build/ makefiles to build latency-collector, inheriting the benefits of it. For example: Before this patch, a missing tracefs/traceevents headers will result in fail like this: ~/linux/tools/tracing/latency $ make cc -Wall -Wextra -g -O2 -o latency-collector latency-collector.c -lpthread latency-collector.c:26:10: fatal error: tracefs.h: No such file or directory 26 | #include <tracefs.h> | ^~~~~~~~~~~ compilation terminated. make: *** [Makefile:14: latency-collector] Error 1 Which is not that helpful. After this change it reports: ~/linux/tools/tracing/latency# make Auto-detecting system features: ... libtraceevent: [ OFF ] ... libtracefs: [ OFF ] libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel libtracefs is missing. Please install libtracefs-dev/libtracefs-devel Makefile.config:29: *** Please, check the errors above.. Stop. This type of output is common across other tools in tools/ like perf and objtool. Link: https://lkml.kernel.org/r/872420b0880b11304e4ba144a0086c6478c5b469.1710519524.git.bristot@kernel.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Use tools/build/ makefiles to build latency-collector, inheriting
the benefits of it. For example: Before this patch, a missing
tracefs/traceevents headers will result in fail like this:

  ~/linux/tools/tracing/latency $ make
  cc -Wall -Wextra -g -O2  -o latency-collector latency-collector.c -lpthread
  latency-collector.c:26:10: fatal error: tracefs.h: No such file or directory
     26 | #include <tracefs.h>
        |          ^~~~~~~~~~~
  compilation terminated.
  make: *** [Makefile:14: latency-collector] Error 1

Which is not that helpful. After this change it reports:

  ~/linux/tools/tracing/latency# make

  Auto-detecting system features:
  ...                           libtraceevent: [ OFF ]
  ...                              libtracefs: [ OFF ]

  libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel
  libtracefs is missing. Please install libtracefs-dev/libtracefs-devel
  Makefile.config:29: *** Please, check the errors above..  Stop.

This type of output is common across other tools in tools/ like perf
and objtool.

Link: https://lkml.kernel.org/r/872420b0880b11304e4ba144a0086c6478c5b469.1710519524.git.bristot@kernel.org

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Exit with EXIT_SUCCESS when help is invoked 2024-02-12T09:59:09+00:00 John Kacur jkacur@redhat.com 2024-02-03T00:16:07+00:00 b5f319360371087d52070d8f3fc7789e80ce69a6 Fix rtla so that the following commands exit with 0 when help is invoked rtla osnoise top -h rtla osnoise hist -h rtla timerlat top -h rtla timerlat hist -h Link: https://lore.kernel.org/linux-trace-devel/20240203001607.69703-1-jkacur@redhat.com Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Fix rtla so that the following commands exit with 0 when help is invoked

rtla osnoise top -h
rtla osnoise hist -h
rtla timerlat top -h
rtla timerlat hist -h

Link: https://lore.kernel.org/linux-trace-devel/20240203001607.69703-1-jkacur@redhat.com

Cc: stable@vger.kernel.org
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Replace setting prio with nice for SCHED_OTHER 2024-02-12T09:56:36+00:00 limingming3 limingming890315@gmail.com 2024-02-07T06:51:42+00:00 14f08c976ffe0d2117c6199c32663df1cbc45c65 Since the sched_priority for SCHED_OTHER is always 0, it makes no sence to set it. Setting nice for SCHED_OTHER seems more meaningful. Link: https://lkml.kernel.org/r/20240207065142.1753909-1-limingming3@lixiang.com Cc: stable@vger.kernel.org Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: limingming3 <limingming3@lixiang.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Since the sched_priority for SCHED_OTHER is always 0, it makes no
sence to set it.
Setting nice for SCHED_OTHER seems more meaningful.

Link: https://lkml.kernel.org/r/20240207065142.1753909-1-limingming3@lixiang.com

Cc: stable@vger.kernel.org
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Signed-off-by: limingming3 <limingming3@lixiang.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Remove unused sched_getattr() function 2024-02-12T08:57:37+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-02-06T11:05:32+00:00 084ce16df0f060efd371092a09a7ae74a536dc11 Clang is reporting: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:241:19: warning: unused function 'sched_getattr' [-Wunused-function] 241 | static inline int sched_getattr(pid_t pid, struct sched_attr *attr, | ^~~~~~~~~~~~~ 1 warning generated. Which is correct, so remove the unused function. Link: https://lkml.kernel.org/r/eaed7ba122c4ae88ce71277c824ef41cbf789385.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Clang is reporting:

$ make HOSTCC=clang CC=clang LLVM_IAS=1
[...]
clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection  -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs)    -c -o src/utils.o src/utils.c
src/utils.c:241:19: warning: unused function 'sched_getattr' [-Wunused-function]
  241 | static inline int sched_getattr(pid_t pid, struct sched_attr *attr,
      |                   ^~~~~~~~~~~~~
1 warning generated.

Which is correct, so remove the unused function.

Link: https://lkml.kernel.org/r/eaed7ba122c4ae88ce71277c824ef41cbf789385.1707217097.git.bristot@kernel.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Donald Zickus <dzickus@redhat.com>
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Fix clang warning about mount_point var size 2024-02-12T08:57:14+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-02-06T11:05:31+00:00 30369084ac6e27479a347899e74f523e6ca29b89 clang is reporting this warning: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:548:66: warning: 'fscanf' may overflow; destination buffer in argument 3 has size 1024, but the corresponding specifier may require size 1025 [-Wfortify-source] 548 | while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) { | ^ Increase mount_point variable size to MAX_PATH+1 to avoid the overflow. Link: https://lkml.kernel.org/r/1b46712e93a2f4153909514a36016959dcc4021c.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
clang is reporting this warning:

$ make HOSTCC=clang CC=clang LLVM_IAS=1
[...]
clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions
	-fstack-protector-strong -fasynchronous-unwind-tables
	-fstack-clash-protection  -Wall -Werror=format-security
	-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
	$(pkg-config --cflags libtracefs)    -c -o src/utils.o src/utils.c

src/utils.c:548:66: warning: 'fscanf' may overflow; destination buffer in argument 3 has size 1024, but the corresponding specifier may require size 1025 [-Wfortify-source]
  548 |         while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) {
      |                                                                         ^

Increase mount_point variable size to MAX_PATH+1 to avoid the overflow.

Link: https://lkml.kernel.org/r/1b46712e93a2f4153909514a36016959dcc4021c.1707217097.git.bristot@kernel.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Donald Zickus <dzickus@redhat.com>
Fixes: a957cbc02531 ("rtla: Add -C cgroup support")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Fix uninitialized bucket/data->bucket_size warning 2024-02-12T08:56:22+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-02-06T11:05:30+00:00 64dc40f7523369912d7adb22c8cb655f71610505 When compiling rtla with clang, I am getting the following warnings: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [..] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/osnoise_hist.o src/osnoise_hist.c src/osnoise_hist.c:138:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/osnoise_hist.c:149:6: note: uninitialized use occurs here 149 | if (bucket < entries) | ^~~~~~ src/osnoise_hist.c:138:2: note: remove the 'if' if its condition is always true 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 139 | bucket = duration / data->bucket_size; src/osnoise_hist.c:132:12: note: initialize the variable 'bucket' to silence this warning 132 | int bucket; | ^ | = 0 1 warning generated. [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/timerlat_hist.o src/timerlat_hist.c src/timerlat_hist.c:181:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/timerlat_hist.c:204:6: note: uninitialized use occurs here 204 | if (bucket < entries) | ^~~~~~ src/timerlat_hist.c:181:2: note: remove the 'if' if its condition is always true 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 182 | bucket = latency / data->bucket_size; src/timerlat_hist.c:175:12: note: initialize the variable 'bucket' to silence this warning 175 | int bucket; | ^ | = 0 1 warning generated. This is a legit warning, but data->bucket_size is always > 0 (see timerlat_hist_parse_args()), so the if is not necessary. Remove the unneeded if (data->bucket_size) to avoid the warning. Link: https://lkml.kernel.org/r/6e1b1665cd99042ae705b3e0fc410858c4c42346.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
When compiling rtla with clang, I am getting the following warnings:

$ make HOSTCC=clang CC=clang LLVM_IAS=1

[..]
clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions
	-fstack-protector-strong -fasynchronous-unwind-tables
	-fstack-clash-protection  -Wall -Werror=format-security
	-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
	$(pkg-config --cflags libtracefs)
	-c -o src/osnoise_hist.o src/osnoise_hist.c
src/osnoise_hist.c:138:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
  138 |         if (data->bucket_size)
      |             ^~~~~~~~~~~~~~~~~
src/osnoise_hist.c:149:6: note: uninitialized use occurs here
  149 |         if (bucket < entries)
      |             ^~~~~~
src/osnoise_hist.c:138:2: note: remove the 'if' if its condition is always true
  138 |         if (data->bucket_size)
      |         ^~~~~~~~~~~~~~~~~~~~~~
  139 |                 bucket = duration / data->bucket_size;
src/osnoise_hist.c:132:12: note: initialize the variable 'bucket' to silence this warning
  132 |         int bucket;
      |                   ^
      |                    = 0
1 warning generated.

[...]

clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions
	-fstack-protector-strong -fasynchronous-unwind-tables
	-fstack-clash-protection  -Wall -Werror=format-security
	-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
	$(pkg-config --cflags libtracefs)
	-c -o src/timerlat_hist.o src/timerlat_hist.c
src/timerlat_hist.c:181:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
  181 |         if (data->bucket_size)
      |             ^~~~~~~~~~~~~~~~~
src/timerlat_hist.c:204:6: note: uninitialized use occurs here
  204 |         if (bucket < entries)
      |             ^~~~~~
src/timerlat_hist.c:181:2: note: remove the 'if' if its condition is always true
  181 |         if (data->bucket_size)
      |         ^~~~~~~~~~~~~~~~~~~~~~
  182 |                 bucket = latency / data->bucket_size;
src/timerlat_hist.c:175:12: note: initialize the variable 'bucket' to silence this warning
  175 |         int bucket;
      |                   ^
      |                    = 0
1 warning generated.

This is a legit warning, but data->bucket_size is always > 0 (see
timerlat_hist_parse_args()), so the if is not necessary.

Remove the unneeded if (data->bucket_size) to avoid the warning.

Link: https://lkml.kernel.org/r/6e1b1665cd99042ae705b3e0fc410858c4c42346.1707217097.git.bristot@kernel.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Donald Zickus <dzickus@redhat.com>
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
tools/rtla: Fix Makefile compiler options for clang 2024-02-12T08:49:13+00:00 Daniel Bristot de Oliveira bristot@kernel.org 2024-02-06T11:05:29+00:00 bc4cbc9d260ba8358ca63662919f4bb223cb603b The following errors are showing up when compiling rtla with clang: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc1\" -flto=auto -ffat-lto-objects -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument] warning: unknown warning option '-Wno-maybe-uninitialized'; did you mean '-Wno-uninitialized'? [-Wunknown-warning-option] 1 warning generated. clang -o rtla -ggdb src/osnoise.o src/osnoise_hist.o src/osnoise_top.o src/rtla.o src/timerlat_aa.o src/timerlat.o src/timerlat_hist.o src/timerlat_top.o src/timerlat_u.o src/trace.o src/utils.o $(pkg-config --libs libtracefs) src/osnoise.o: file not recognized: file format not recognized clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Makefile:110: rtla] Error 1 Solve these issues by: - removing -ffat-lto-objects and -Wno-maybe-uninitialized if using clang - informing the linker about -flto=auto Link: https://lore.kernel.org/linux-trace-kernel/567ac1b94effc228ce9a0225b9df7232a9b35b55.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Fixes: 1a7b22ab15eb ("tools/rtla: Build with EXTRA_{C,LD}FLAGS") Suggested-by: Donald Zickus <dzickus@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
The following errors are showing up when compiling rtla with clang:

 $ make HOSTCC=clang CC=clang LLVM_IAS=1
 [...]

  clang -O -g -DVERSION=\"6.8.0-rc1\" -flto=auto -ffat-lto-objects
	-fexceptions -fstack-protector-strong
	-fasynchronous-unwind-tables -fstack-clash-protection  -Wall
	-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
	-Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized
	$(pkg-config --cflags libtracefs)    -c -o src/utils.o src/utils.c

  clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument]
  warning: unknown warning option '-Wno-maybe-uninitialized'; did you mean '-Wno-uninitialized'? [-Wunknown-warning-option]
  1 warning generated.

  clang -o rtla -ggdb  src/osnoise.o src/osnoise_hist.o src/osnoise_top.o
  src/rtla.o src/timerlat_aa.o src/timerlat.o src/timerlat_hist.o
  src/timerlat_top.o src/timerlat_u.o src/trace.o src/utils.o $(pkg-config --libs libtracefs)

  src/osnoise.o: file not recognized: file format not recognized
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  make: *** [Makefile:110: rtla] Error 1

Solve these issues by:
  - removing -ffat-lto-objects and -Wno-maybe-uninitialized if using clang
  - informing the linker about -flto=auto

Link: https://lore.kernel.org/linux-trace-kernel/567ac1b94effc228ce9a0225b9df7232a9b35b55.1707217097.git.bristot@kernel.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Fixes: 1a7b22ab15eb ("tools/rtla: Build with EXTRA_{C,LD}FLAGS")
Suggested-by: Donald Zickus <dzickus@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
rtla: Fix uninitialized variable found 2023-10-30T18:00:12+00:00 Colin Ian King colin.i.king@gmail.com 2023-07-27T15:01:17+00:00 696444a544ecd6d62c1edc89516b376cefb28929 Variable found is not being initialized, in the case where the desired mount is not found the variable contains garbage. Fix this by initializing it to zero. Link: https://lore.kernel.org/all/20230727150117.627730-1-colin.i.king@gmail.com/ Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> 
Variable found is not being initialized, in the case where the desired
mount is not found the variable contains garbage. Fix this by initializing
it to zero.

Link: https://lore.kernel.org/all/20230727150117.627730-1-colin.i.king@gmail.com/

Fixes: a957cbc02531 ("rtla: Add -C cgroup support")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>