On 01/21/2015 06:21 PM, Huang Ying wrote:
FYI, we noticed the below changes on
commit 34b48db66e08ca1c1bc07cf305d672ac940268dc ("block: remove artifical
max_hw_sectors cap")
testbox/testcase/testparams:
lkp-ws02/fileio/600s-100%-1HDD-btrfs-64G-1024f-seqrewr-sync
c2661b806092d8ea 34b48db66e08ca1c1bc07cf305
---------------- --------------------------
%stddev %change %stddev
\ | \
47176 ± 2% -67.3% 15406 ± 4% softirqs.BLOCK
1110 ± 44% -51.0% 544 ± 35% sched_debug.cpu#8.curr->pid
22 ± 33% -48.9% 11 ± 43% sched_debug.cpu#1.cpu_load[0]
91 ± 43% +125.0% 204 ± 32%
sched_debug.cfs_rq[4]:/.blocked_load_avg
17 ± 46% -65.2% 6 ± 31%
sched_debug.cfs_rq[1]:/.runnable_load_avg
105 ± 43% +102.6% 213 ± 32%
sched_debug.cfs_rq[4]:/.tg_load_contrib
163 ± 35% +62.6% 265 ± 27%
sched_debug.cfs_rq[16]:/.blocked_load_avg
183 ± 29% +51.4% 277 ± 26%
sched_debug.cfs_rq[16]:/.tg_load_contrib
1411 ± 31% -42.5% 812 ± 32% sched_debug.cpu#6.curr->pid
57565068 ± 15% +66.8% 96024066 ± 17% cpuidle.C1E-NHM.time
94625 ± 9% -32.5% 63893 ± 4% cpuidle.C3-NHM.usage
200 ± 14% -22.8% 155 ± 24%
sched_debug.cfs_rq[8]:/.tg_load_contrib
244 ± 33% -39.0% 149 ± 11%
sched_debug.cfs_rq[6]:/.blocked_load_avg
265 ± 31% -38.4% 163 ± 9%
sched_debug.cfs_rq[6]:/.tg_load_contrib
4959 ± 9% -18.2% 4058 ± 1% slabinfo.kmalloc-128.active_objs
4987 ± 9% -18.6% 4058 ± 1% slabinfo.kmalloc-128.num_objs
19 ± 8% -19.7% 15 ± 14% sched_debug.cpu#0.cpu_load[1]
662307 ± 7% -12.6% 579108 ± 3% cpuidle.C6-NHM.usage
3028 ± 7% -12.3% 2656 ± 1%
slabinfo.ext4_extent_status.num_objs
3028 ± 7% -12.3% 2656 ± 1%
slabinfo.ext4_extent_status.active_objs
4.87 ± 0% +3291.6% 165.07 ± 0% iostat.sde.wrqm/s
1006 ± 0% +120.3% 2216 ± 0% iostat.sde.avgrq-sz
So these two above tells us that we are doing way more write merges per
second, and that the average request size has roughly doubled from 1006
to 2216 - both are excellent news.
466 ± 0% +115.9% 1007 ± 0% iostat.sde.await
466 ± 0% +115.9% 1007 ± 0% iostat.sde.w_await
Service time roughly doubled, must be mostly stream time.
301 ± 0% -52.7% 142 ± 0% iostat.sde.w/s
About half the number of writes completed, but from the stats above,
those writes are more than double. 1006 * 301 < 2216 * 142, so again,
this looks good.
2230 ± 2% -8.2% 2048 ± 2% vmstat.system.in
And a nice reduction in irq rate, also nice. Way less software irqs from
the first few lines, also a win.
--
Jens Axboe
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