The first field of /proc/uptime relies on the CLOCK_BOOTTIME clock which
can also be fetched from clock_gettime() API.
Improve the test coverage while verifying the monotonicity of
CLOCK_BOOTTIME accross both interfaces.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230222144649.624380-9-frederic@kernel.org
Due to broken iowait task counting design (cf: comments above
get_cpu_idle_time_us() and nr_iowait()), it is not possible to provide
the guarantee that /proc/stat or /proc/uptime display monotonic idle
time values.
Remove the assertions that verify the related wrong assumption so that
testers and maintainers don't spend more time on that.
Reported-by: Yu Liao <liaoyu15@huawei.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230222144649.624380-8-frederic@kernel.org
syscall(3) returns -1 and sets errno on error, unlike "syscall"
instruction.
Systems which have <= 32/64 CPUs are unaffected. Test won't bounce
to all CPUs before completing if there are more of them.
Link: https://lkml.kernel.org/r/Y1bUiT7VRXlXPQa1@p183
Fixes: 1f5bd05476 ("proc: selftests: test /proc/uptime")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Makefile already contains -D_GNU_SOURCE, so we can remove it from the
*.c files.
Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Add copyright in two files before they get autorubberstamped.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The only tests I could come up with for /proc/uptime are:
- test that values increase monotonically for 1 second,
- bounce around CPUs and test the same thing.
Avoid glibc like plague for affinity given patches like this:
https://marc.info/?l=linux-kernel&m=152130031912594&w=4
Link: http://lkml.kernel.org/r/20180317165235.GB3445@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
