On Thu, Feb 16, 2023 at 3:52 PM Jonathan Derrick <jonathan.derrick@xxxxxxxxx> wrote: > > > > On 2/10/2023 10:32 AM, Song Liu wrote: > > Hi Jonathan, > > > > On Thu, Feb 9, 2023 at 12:38 PM Jonathan Derrick > > <jonathan.derrick@xxxxxxxxx> wrote: > >> > >> Hi Song, > >> > >> Any thoughts on this? > > > > I am really sorry that I missed this patch. > > > >> > >> On 1/17/2023 5:53 PM, Jonathan Derrick wrote: > >>> From: Jon Derrick <jonathan.derrick@xxxxxxxxx> > >>> > >>> If the bitmap space has enough room, size the I/O for the last bitmap > >>> page write to the optimal I/O size for the storage device. The expanded > >>> write is checked that it won't overrun the data or metadata. > >>> > >>> This change helps increase performance by preventing unnecessary > >>> device-side read-mod-writes due to non-atomic write unit sizes. > >>> > >>> Ex biosnoop log. Device lba size 512, optimal size 4k: > >>> Before: > >>> Time Process PID Device LBA Size Lat > >>> 0.843734 md0_raid10 5267 nvme0n1 W 24 3584 1.17 > >>> 0.843933 md0_raid10 5267 nvme1n1 W 24 3584 1.36 > >>> 0.843968 md0_raid10 5267 nvme1n1 W 14207939968 4096 0.01 > >>> 0.843979 md0_raid10 5267 nvme0n1 W 14207939968 4096 0.02 > >>> > >>> After: > >>> Time Process PID Device LBA Size Lat > >>> 18.374244 md0_raid10 6559 nvme0n1 W 24 4096 0.01 > >>> 18.374253 md0_raid10 6559 nvme1n1 W 24 4096 0.01 > >>> 18.374300 md0_raid10 6559 nvme0n1 W 11020272296 4096 0.01 > >>> 18.374306 md0_raid10 6559 nvme1n1 W 11020272296 4096 0.02 > > > > Do we see significant improvements from io benchmarks? > Yes. With lbaf=512, optimal i/o size=4k: > > Without patch: > write: IOPS=1570, BW=6283KiB/s (6434kB/s)(368MiB/60001msec); 0 zone resets > With patch: > write: IOPS=59.7k, BW=233MiB/s (245MB/s)(13.7GiB/60001msec); 0 zone resets The difference is much bigger than I expected. Given this big improvements, I think we should ship this improvement. Unfortunately, we are too late for 6.3. Let's plan to ship this in the 6.4 release. I am on vacation this week. I will work on this afterwards. Thanks, Song
