02/11/2017 11:58, Li, Xiaoyun: > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > 02/11/2017 11:22, Wang, Zhihong: > > > > I don't know what is creating this drop exactly. > > > > When doing different tests on different environments, we do not see > > > > this drop. > > > > If nobody else can see such issue, I guess we can ignore it. > > > > > > Hi Thomas, Xiaoyun, > > > > > > With this patch (commit 84cc318424d49372dd2a5fbf3cf84426bf95acce) I > > > see more than 20% performance drop in vhost loopback test with testpmd > > > macswap for 256 bytes packets, which means it impacts actual > > > vSwitching performance. > > > > > > Suggest we fix it or revert it for this release. > > > > I think we need more numbers to take a decision. > > What is the benefit of this patch? In which use-cases? > > The benefit is that if compile it on a lower platform (such as only supports > SSE), > when it run on higher platforms (such as AVX2 or AVX512). It would still can > get ISA benefit (AVX2).
Yes, but you don't provide any number here. > User case seems to be that some customers want it in cloud environment and > don't want to compile on all platforms. > > > What are the drawbacks? In which use-cases? > > The drawback is perf drop. So far, see lot of drop in mellanox case and vhost > case. > > Should I send the revert patch or you revert it directly? You should send the revert yourself with some good justifications. I did not ask some numbers when accepting the patch (my mistake). Please provide the numbers for the revert. > > Please, it is a call to test performance with and without this patch in more > > environments (CPU, packet size, applications). Who can test it in more environments?
