At Fri, 7 Jun 2013 09:26:58 +0800, Jianguo Wu wrote: > > Hi Hitoshi, > > Thanks for your reply! please see below. > > On 2013/6/6 21:54, Hitoshi Mitake wrote: > > > Hi Jianguo, > > > > On Wed, Jun 5, 2013 at 12:26 PM, Jianguo Wu <wujianguo@xxxxxxxxxx> wrote: > >> Hi, > >> One more question, I wrote a memcpy test program, mostly the same as with perf bench memcpy. > >> But test result isn't consistent with perf bench when THP is off. > >> > >> my program perf bench > >> THP: 3.628368 GB/Sec (with prefault) 3.672879 GB/Sec (with prefault) > >> NO-THP: 3.612743 GB/Sec (with prefault) 6.190187 GB/Sec (with prefault) > >> > >> Below is my code: > >> src = calloc(1, len); > >> dst = calloc(1, len); > >> > >> if (prefault) > >> memcpy(dst, src, len); > >> gettimeofday(&tv_start, NULL); > >> memcpy(dst, src, len); > >> gettimeofday(&tv_end, NULL); > >> > >> timersub(&tv_end, &tv_start, &tv_diff); > >> free(src); > >> free(dst); > >> > >> speed = (double)((double)len / timeval2double(&tv_diff)); > >> print_bps(speed); > >> > >> This is weird, is it possible that perf bench do some build optimize? > >> > >> Thansk, > >> Jianguo Wu. > > > > perf bench mem memcpy is build with -O6. This is the compile command > > line (you can get this with make V=1): > > gcc -o bench/mem-memcpy-x86-64-asm.o -c -fno-omit-frame-pointer -ggdb3 > > -funwind-tables -Wall -Wextra -std=gnu99 -Werror -O6 .... # ommited > > > > Can I see your compile option for your test program and the actual > > command line executing perf bench mem memcpy? > > > > I just compiled my test program with gcc -o memcpy-test memcpy-test.c. > I tried to use the same compile option with perf bench mem memcpy, and > the test result showed no difference. > > My execute command line for perf bench mem memcpy: > #./perf bench mem memcpy -l 1gb -o Thanks for your information. I have three more requests for reproducing the problem: 1. the entire source code of your program 2. your gcc version 3. your glibc version I should've requested it first, sorry :( Thanks, Hitoshi -- 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>