cfq: always return false from should_idle if slice_idle is set to zero
in [Kernel]
|
Prev: netdev: add tracepoints to netdev layer
Next: Ext4: Make file creation time, i_version and i_generation available by xattrs
From: Jeff Moyer on 28 Jun 2010 14:50 Jens Axboe <axboe(a)kernel.dk> writes: > 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. So.... applied to which branch? Thanks! Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jeff Moyer on 28 Jun 2010 15:00
Jens Axboe <axboe(a)kernel.dk> writes: > On 28/06/10 20.41, Jeff Moyer wrote: >> Jens Axboe <axboe(a)kernel.dk> writes: >> >>> 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. >> >> So.... applied to which branch? > > Not applied yet, unless I explicitly say it's applied, then it's not > necessarily in any public git tree yet. But this will go into .35. OK, thanks for the clarification. Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |