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2019-03-19perf tools: Fix errors under optimization level '-Og'Changbin Du
Optimization level '-Og' offers a reasonable level of optimization while maintaining fast compilation and a good debugging experience. This patch tries to make it work. $ make DEBUG=1 EXTRA_CFLAGS='-Og' bench/epoll-ctl.c: In function ‘do_threads’: bench/epoll-ctl.c:274:9: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized] return ret; ^~~ ... Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20190316080556.3075-4-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-11-21perf bench: Add epoll parallel epoll_wait benchmarkDavidlohr Bueso
This program benchmarks concurrent epoll_wait(2) for file descriptors that are monitored with with EPOLLIN along various semantics, by a single epoll instance. Such conditions can be found when using single/combined or multiple queuing when load balancing. Each thread has a number of private, nonblocking file descriptors, referred to as fdmap. A writer thread will constantly be writing to the fdmaps of all threads, minimizing each threads's chances of epoll_wait not finding any ready read events and blocking as this is not what we want to stress. Full details in the start of the C file. Committer testing: # perf bench Usage: perf bench [<common options>] <collection> <benchmark> [<options>] # List of all available benchmark collections: sched: Scheduler and IPC benchmarks mem: Memory access benchmarks numa: NUMA scheduling and MM benchmarks futex: Futex stressing benchmarks epoll: Epoll stressing benchmarks all: All benchmarks # perf bench epoll # List of available benchmarks for collection 'epoll': wait: Benchmark epoll concurrent epoll_waits all: Run all futex benchmarks # perf bench epoll wait # Running 'epoll/wait' benchmark: Run summary [PID 19295]: 3 threads monitoring on 64 file-descriptors for 8 secs. [thread 0] fdmap: 0xdaa650 ... 0xdaa74c [ 328241 ops/sec ] [thread 1] fdmap: 0xdaa900 ... 0xdaa9fc [ 351695 ops/sec ] [thread 2] fdmap: 0xdaabb0 ... 0xdaacac [ 381423 ops/sec ] Averaged 353786 operations/sec (+- 4.35%), total secs = 8 # Committer notes: Fix the build on debian:experimental-x-mips, debian:experimental-x-mipsel and others: CC /tmp/build/perf/bench/epoll-wait.o bench/epoll-wait.c: In function 'writerfn': bench/epoll-wait.c:399:12: error: format '%ld' expects argument of type 'long int', but argument 2 has type 'size_t' {aka 'unsigned int'} [-Werror=format=] printinfo("exiting writer-thread (total full-loops: %ld)\n", iter); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~ bench/epoll-wait.c:86:31: note: in definition of macro 'printinfo' do { if (__verbose) { printf(fmt, ## arg); fflush(stdout); } } while (0) ^~~ cc1: all warnings being treated as errors Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> <jbaron@akamai.com> Link: http://lkml.kernel.org/r/20181106152226.20883-2-dave@stgolabs.net Link: http://lkml.kernel.org/r/20181106182349.thdkpvshkna5vd7o@linux-r8p5> [ Applied above fixup as per Davidlohr's request ] [ Use inttypes.h to print rlim_t fields, fixing the build on Alpine Linux / musl libc ] [ Check if eventfd() is available, i.e. if HAVE_EVENTFD is defined ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>