"Li, Liang Z" <liang.z...@intel.com> wrote: >> On 12/11/2015 10:40, Li, Liang Z wrote: >> > I migrate a 8GB RAM Idle guest, I think most of it's pages are zero pages. >> > >> > I use your new code: >> > ------------------------------------------------- >> > unsigned long *p = ... >> > if (p[0] || p[1] || p[2] || p[3] >> > || memcmp(p+4, p, size - 4 * sizeof(unsigned long)) != 0) >> > return BUFFER_NOT_ZERO; >> > else >> > return BUFFER_ZERO; >> > --------------------------------------------------- >> > and the result is almost the same. I also tried the check 8, 16 long >> > data at the beginning, same result. >> >> Interesting... Well, all I can say is that applaud you for testing >> your hypothesis >> with the benchmark. >> >> Probably the setup cost of memcmp is too high, because the testing loop is >> already very optimized. >> >> Please submit the AVX2 version if it helps!
I read the email in the wrong order. Forget about my other email. Sorry, Juan. > > Yes, the AVX2 version really helps. I have already submitted it, could > you help to review it? > > I am curious about the original intention to add the SSE2 Intrinsics, > is the same reason? > > I even suspect the VM may impact the 'memcmp()' performance, is it possible? > > Liang > >> Paolo
