On Tue, Dec 29, 2015 at 10:19:17AM -0700, Jens Axboe wrote: > On 12/28/2015 06:08 PM, Alexandru Moise wrote: > >This patch refers to Jens Axboe's change way back in 2006: > >7b14e3b52 cfq-iosched: slice expiry fixups > > > >In this patch he fixed a potential timer race condition by delaying > >idle_slice_timer by the slice_idle time value. > > > >Today this timer is delayed by either slice_idle or group_idle time > >values, which on my system, and according to > >Documentation/block/cfq-iosched.txt the default value for both is 8ms. > > > >Since the time given by either variables is supposed to be in > >milliseconds we should convert that value from milliseconds to jiffies > >before adding it to jiffies variable and setting our timer. > > > >In my obervations the area is really active as I've seen that function > >get called a lot for each device on my btrfs raid setup during btrfs > >check. I've also timed the btrfs check before and after applying the > >patch and I might've noticed a very slight improvement in execution > >time but the numbers vary too much for me to post any believable > >numbers (10 milliseconds difference at most on average). > > cfqd->cfq_slice_idle is in jiffies, it's not in msecs. > > -- > Jens Axboe > Then should I only do the conversion in the case of group_idle? -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
