When building with clang on a musl libc system, Alpine Linux, we end up
hitting a problem where memset() is used but its prototype is not
present, add it to avoid this:
bench/futex-wake.c:99:3: error: implicitly declaring library function 'memset' with type 'void *(void *, int, unsigned long)'
[-Werror,-Wimplicit-function-declaration]
CPU_ZERO(&cpu);
^
/usr/include/sched.h:127:23: note: expanded from macro 'CPU_ZERO'
#define CPU_ZERO(set) CPU_ZERO_S(sizeof(cpu_set_t),set)
^
/usr/include/sched.h:110:30: note: expanded from macro 'CPU_ZERO_S'
#define CPU_ZERO_S(size,set) memset(set,0,size)
^
bench/futex-wake.c:99:3: note: include the header <string.h> or explicitly provide a declaration for 'memset'
Found while updating my test build containers to build perf with clang in more
systems.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-jh10vaz2r98zl6gm5iau8prr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This reverts commit 60758d6668.
Now that libsubcmd makes sure that OPT_UINTEGER options will not
return negative values, we can revert this patch while addressing
the problem it solved:
# perf bench futex hash -t -4
# Running 'futex/hash' benchmark:
Error: switch `t' expects an unsigned numerical value
Usage: perf bench futex hash <options>
-t, --threads <n> Specify amount of threads
# perf bench futex hash -t-4
# Running 'futex/hash' benchmark:
Error: switch `t' expects an unsigned numerical value
Usage: perf bench futex hash <options>
-t, --threads <n> Specify amount of threads
#
IMO it is more reasonable to flat out refuse to process a negative
number than to silently turn it into an absolute value.
This also helps in silencing clang's complaint about asking for an
absolute value of an unsigned integer:
bench/futex-hash.c:133:10: error: taking the absolute value of unsigned type 'unsigned int' has no effect [-Werror,-Wabsolute-value]
nsecs = futexbench_sanitize_numeric(nsecs);
^
bench/futex.h:104:42: note: expanded from macro 'futexbench_sanitize_numeric'
#define futexbench_sanitize_numeric(__n) abs((__n))
^
bench/futex-hash.c:133:10: note: remove the call to 'abs' since unsigned values cannot be negative
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2kl68v22or31vw643m2exz8x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Block a bunch of threads on a futex and wake them up, N at a time.
This program is particularly useful to measure the latency of nthread
wakeups in non-error situations: all waiters are queued and all wake
calls wakeup one or more tasks.
An example run:
$ perf bench futex wake -t 512 -r 100
Run summary [PID 27823]: blocking on 512 threads (at futex 0x7e10d4), waking up 1 at a time.
[Run 1]: Wokeup 512 of 512 threads in 6.0080 ms
[Run 2]: Wokeup 512 of 512 threads in 5.2280 ms
[Run 3]: Wokeup 512 of 512 threads in 4.8300 ms
...
[Run 100]: Wokeup 512 of 512 threads in 5.0100 ms
Wokeup 512 of 512 threads in 5.0109 ms (+-2.25%)
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1387081917-9102-3-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
