On Fri, Apr 17, 2015 at 10:02:30AM +0800, Fam Zheng wrote: > On Thu, 04/16 14:03, Stefan Hajnoczi wrote: > > On Thu, Apr 16, 2015 at 12:57:29PM +0800, Fam Zheng wrote: > > > v3: Rebase to master for 2.4. > > > Although epoll_pwait1 syscall is still being worked on [1], the QEMU > > > part > > > (if any) will base on this, so let's merge it first. > > > > > > That part is not included in this version because I'm still > > > evaluating by > > > comparing epoll_pwait1 with epoll+timerfd as with current master they > > > seem > > > to be really close. > > > > > > [1]: http://www.spinics.net/lists/linux-api/msg08216.html > > > > > > v2: Emulate nanoseconds precison of timeout with ppoll and timerfd. > > > Their performance is on par with each other, but both much better than > > > qemu.git: > > > > > > syscall high # of fd low # of fd > > > ------------------------------------------------- > > > qemu.git(ppoll) 44 96 > > > ppoll+epoll 85 101 > > > timerfd+epoll 87 109 > > > > > > (In high # of fd case, 3 activated but idle virtio-console devices are > > > attached, which will add us hundereds of fds to poll) > > > > Have you rerun benchmarks with this patch series? > > Yes, here: > > syscall high # of fd low # of fd > (Unit MB/s) (Unit MB/s) > ------------------------------------------------- > qemu.git(ppoll) 24 73 > ppoll+epoll 49 77 > timerfd+epoll 49 82
Nice. Weird that the results are much lower than the v2 results, but maybe the host changed? > > > > I wonder how the ppoll-only performance changes. It seems like there > > are now additional copies of <fd, events, revents> information and > > corresponding malloc/realloc/frees. Please add a ppoll-only column hosts so we can be confident that the non-epoll code works. It will also show that non-Linux POSIX hosts haven't regressed. Thanks, Stefan
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