Messages in this thread | | | Date | Mon, 21 Jun 2010 22:00:10 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH 1/2] cfq: always return false from should_idle if slice_idle is set to zero |
| |
On 21/06/10 21.49, Jeff Moyer wrote: > Hi, > > In testing a competing fsync-ing process and a sequential reader on > mid-grade storage, I found that cfq was incapable of achieving the I/O > rates of deadline, no matter how it was tuned. Investigation, and insight > from Vivek (mostly the latter), led to identifying that we were still > idling for the last queue in the service tree. > > Modifying cfq_should_idle to not idle when slice_idle is set to zero got > us much closer to the performance of deadline for this workload. I have > one follow-on patch that gets us on-par with deadline, but I think this > patch stands alone. > > Comments, as always, are appreciated.
This looks good.
-- Jens Axboe
| |