On Sun, Dec 15, 2013 at 10:34:25AM -0800, Linus Torvalds wrote: > On Sun, Dec 15, 2013 at 7:55 AM, Mel Gorman <mgorman@xxxxxxx> wrote: > > > > Short answer -- There appears to be a second bug where 3.13-rc3 is less > > fair to threads getting time on the CPU. > > Hmm. Can you point me at the (fixed) microbenchmark you mention? > ebizzy is what I was using to see the per-thread performance. It's at http://sourceforge.net/projects/ebizzy/. It's patched with the patch below to give per-thread stats. You probably want to run it manually but FWIW, the results I posted were using mmtests (https://github.com/gormanm/mmtests) to build, patch, run ebizzy and generate the report. The configuration file I used was configs/config-global-dhp__tlbflush-performance. I have not tried a manual performance analysis yet as an automated bisection is in progress to see can the thread spread problem be found the easy way. diff --git a/ebizzy.c b/ebizzy.c index 76c7492..3e7644f 100644 --- a/ebizzy.c +++ b/ebizzy.c @@ -83,7 +83,7 @@ static char **hole_mem; static unsigned int page_size; static time_t start_time; static volatile int threads_go; -static unsigned int records_read; +static unsigned int *thread_records_read; static void usage(void) @@ -436,6 +436,7 @@ search_mem(void) static void * thread_run(void *arg) { + unsigned int *records = (unsigned int *)arg; if (verbose > 1) printf("Thread started\n"); @@ -444,7 +445,7 @@ thread_run(void *arg) while (threads_go == 0); - records_read += search_mem(); + *records = search_mem(); if (verbose > 1) printf("Thread finished, %f seconds\n", @@ -471,12 +472,19 @@ start_threads(void) struct rusage start_ru, end_ru; struct timeval usr_time, sys_time; int err; + unsigned int total_records = 0; if (verbose) printf("Threads starting\n"); + thread_records_read = calloc(threads, sizeof(unsigned int)); + if (!thread_records_read) { + fprintf(stderr, "Error allocating thread_records_read\n"); + exit(1); + } + for (i = 0; i < threads; i++) { - err = pthread_create(&thread_array[i], NULL, thread_run, NULL); + err = pthread_create(&thread_array[i], NULL, thread_run, &thread_records_read[i]); if (err) { fprintf(stderr, "Error creating thread %d\n", i); exit(1); @@ -505,13 +513,21 @@ start_threads(void) fprintf(stderr, "Error joining thread %d\n", i); exit(1); } + total_records += thread_records_read[i]; } if (verbose) printf("Threads finished\n"); - printf("%u records/s\n", - (unsigned int) (((double) records_read)/elapsed)); + printf("%u records/s", + (unsigned int) (((double) total_records)/elapsed)); + + for (i = 0; i < threads; i++) { + printf(" %u", (unsigned int) (((double) thread_records_read[i])/elapsed)); + } + printf("\n"); + + free(thread_records_read); usr_time = difftimeval(&end_ru.ru_utime, &start_ru.ru_utime); sys_time = difftimeval(&end_ru.ru_stime, &start_ru.ru_stime); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>