On Mon, Jan 07, 2019 at 10:19:03AM +0800, Jason Wang wrote: > > On 2019/1/3 上午4:47, Michael S. Tsirkin wrote: > > On Sat, Dec 29, 2018 at 08:46:51PM +0800, Jason Wang wrote: > > > This series tries to access virtqueue metadata through kernel virtual > > > address instead of copy_user() friends since they had too much > > > overheads like checks, spec barriers or even hardware feature > > > toggling. > > Will review, thanks! > > One questions that comes to mind is whether it's all about bypassing > > stac/clac. Could you please include a performance comparison with > > nosmap? > > > > On machine without SMAP (Sandy Bridge): > > Before: 4.8Mpps > > After: 5.2Mpps OK so would you say it's really unsafe versus safe accesses? Or would you say it's just a better written code? > On machine with SMAP (Broadwell): > > Before: 5.0Mpps > > After: 6.1Mpps > > No smap: 7.5Mpps > > > Thanks no smap being before or after? -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
