Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Paolo Bonzini
On 13/03/2015 15:46, Jason Baron wrote: > > The throttling algorithm computes a duration for the next IO, which is used > > to > > arm a timer in order to delay the request a bit. As timers are always > > rounded > > *UP* to the effective granularity, the timeout being 1ms in epoll_pwait is >

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Jason Baron
On 03/13/2015 07:31 AM, Fam Zheng wrote: > On Thu, 03/12 11:02, Jason Baron wrote: >> On 03/09/2015 09:49 PM, Fam Zheng wrote: >> >> Hi, >> >> So it sounds like you are comparing original qemu code (which was using >> ppoll) vs. using epoll with these new syscalls. Curious if you have numbers >>

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Fam Zheng
On Thu, 03/12 11:02, Jason Baron wrote: > On 03/09/2015 09:49 PM, Fam Zheng wrote: > > > > Benchmark for epoll_pwait1 > > == > > > > By running fio tests inside VM with both original and modified QEMU, we can > > compare their difference in performance. > > > > With a small

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Fam Zheng
On Thu, 03/12 11:02, Jason Baron wrote: On 03/09/2015 09:49 PM, Fam Zheng wrote: Benchmark for epoll_pwait1 == By running fio tests inside VM with both original and modified QEMU, we can compare their difference in performance. With a small VM setup [t1],

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Paolo Bonzini
On 13/03/2015 15:46, Jason Baron wrote: The throttling algorithm computes a duration for the next IO, which is used to arm a timer in order to delay the request a bit. As timers are always rounded *UP* to the effective granularity, the timeout being 1ms in epoll_pwait is just

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-13 Thread Jason Baron
On 03/13/2015 07:31 AM, Fam Zheng wrote: On Thu, 03/12 11:02, Jason Baron wrote: On 03/09/2015 09:49 PM, Fam Zheng wrote: Hi, So it sounds like you are comparing original qemu code (which was using ppoll) vs. using epoll with these new syscalls. Curious if you have numbers comparing the

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-12 Thread Jason Baron
On 03/09/2015 09:49 PM, Fam Zheng wrote: > > Benchmark for epoll_pwait1 > == > > By running fio tests inside VM with both original and modified QEMU, we can > compare their difference in performance. > > With a small VM setup [t1], the original QEMU (ppoll based) has an 4k

Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-12 Thread Jason Baron
On 03/09/2015 09:49 PM, Fam Zheng wrote: Benchmark for epoll_pwait1 == By running fio tests inside VM with both original and modified QEMU, we can compare their difference in performance. With a small VM setup [t1], the original QEMU (ppoll based) has an 4k read

[PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-09 Thread Fam Zheng
Changes from v3: - Add "size" field in epoll_wait_params. [Jon, Ingo, Seymour] - Input validation for ncmds in epoll_ctl_batch. [Dan] - Return -EFAULT if copy_to_user failed in epoll_ctl_batch. [Omar, Michael] - Change "timeout" in epoll_wait_params to pointer, to get the same

[PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1

2015-03-09 Thread Fam Zheng
Changes from v3: - Add size field in epoll_wait_params. [Jon, Ingo, Seymour] - Input validation for ncmds in epoll_ctl_batch. [Dan] - Return -EFAULT if copy_to_user failed in epoll_ctl_batch. [Omar, Michael] - Change timeout in epoll_wait_params to pointer, to get the same convention