TO: Rabin Vincent <rabin(a)rab.in&gt; CC: Russell King <rmk+kernel(a)arm.linux.org.uk&gt; CC: LKML <linux-kernel(a)vger.kernel.org&gt; CC: lkp(a)01.org FYI, we noticed the below changes on git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master commit f9ff907b0af561dcde4683f7c9f71dc0f41d3be3 ("ARM: 8048/1: fix v7-M setup stack location") test case: lkp-st02/dd-write/11HDD-RAID5-cfq-ext4-1dd v3.15-rc6 f9ff907b0af561dcde4683f7c --------------- ------------------------- 273 ~ 3% -100.0% 0 ~ 0% TOTAL slabinfo.cfq_queue.num_objs 65541468 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.time 273 ~ 3% -100.0% 0 ~ 0% TOTAL slabinfo.cfq_queue.active_objs 969 ~ 8% -100.0% 0 ~ 0% TOTAL slabinfo.ip6_dst_cache.num_objs 948 ~ 8% -100.0% 0 ~ 0% TOTAL slabinfo.ip6_dst_cache.active_objs 12399 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.balanced_dirty_ratelimit 14234 ~ 2% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.task_ratelimit 10649 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.dirty_ratelimit 17409 ~ 2% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.dirty_rate 13787 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.awrite_bw 14464 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.write_bw 65322936 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.bdi_dirty_ratelimit.md0.time 31 ~ 3% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.dirtied_pause 31 ~ 3% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.dirtied 14350 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.task_ratelimit 10633 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.dirty_ratelimit 13720 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.bdi_dirty 15220 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.bdi_setpoint 13720 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.dirty 15251 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.setpoint 17638 ~ 1% -100.0% 0 ~ 0% TOTAL ftrace.balance_dirty_pages.md0.limit 36455 ~ 0% +221.6% 117256 ~ 0% TOTAL proc-vmstat.unevictable_pgs_culled 986338 ~ 0% -55.5% 438629 ~ 0% TOTAL meminfo.Unevictable 246584 ~ 0% -55.5% 109657 ~ 0% TOTAL proc-vmstat.nr_unevictable 84787 ~20% -47.1% 44851 ~10% TOTAL meminfo.DirectMap4k 11266582 ~ 1% -38.7% 6903348 ~ 0% TOTAL ftrace.writeback_single_inode.md0.index 10996 ~ 9% -25.9% 8143 ~14% TOTAL meminfo.AnonHugePages 1127 ~ 2% +29.8% 1462 ~ 1% TOTAL slabinfo.ftrace_event_file.num_objs 1127 ~ 2% +29.8% 1462 ~ 1% TOTAL slabinfo.ftrace_event_file.active_objs 1.47 ~12% -20.7% 1.17 ~ 7% TOTAL perf-profile.cpu-cycles.do_get_write_access.jbd2_journal_get_write_access.__ext4_journal_get_write_access.ext4_reserve_inode_write.ext4_mark_inode_dirty 15826442 ~ 0% -15.5% 13381229 ~ 0% TOTAL ftrace.global_dirty_state.written 15944180 ~ 0% -15.3% 13502162 ~ 0% TOTAL ftrace.global_dirty_state.dirtied 2906 ~ 1% +14.0% 3314 ~ 1% TOTAL slabinfo.shared_policy_node.active_objs 2906 ~ 1% +14.0% 3314 ~ 1% TOTAL slabinfo.shared_policy_node.num_objs 348891 ~ 0% +14.4% 399046 ~ 0% TOTAL ftrace.global_dirty_state.limit 394528 ~ 0% +11.8% 441163 ~ 0% TOTAL meminfo.MemFree 98671 ~ 0% +11.8% 110310 ~ 0% TOTAL proc-vmstat.nr_free_pages 400850 ~ 0% +11.0% 444838 ~ 0% TOTAL vmstat.memory.free 108208 ~ 0% +11.0% 120084 ~ 0% TOTAL proc-vmstat.nr_dirty 432868 ~ 0% +11.0% 480357 ~ 0% TOTAL meminfo.Dirty 79363 ~ 1% -8.9% 72291 ~ 0% TOTAL proc-vmstat.workingset_nodereclaim 65550 ~ 2% -9.1% 59612 ~ 1% TOTAL softirqs.SCHED 12.06 ~ 5% +530.1% 75.99 ~ 8% TOTAL iostat.sdd.rrqm/s 50.78 ~ 5% +530.2% 320.04 ~ 8% TOTAL iostat.sdd.rkB/s 12.29 ~ 5% +520.0% 76.21 ~ 7% TOTAL iostat.sde.rrqm/s 51.66 ~ 5% +520.9% 320.74 ~ 7% TOTAL iostat.sde.rkB/s 49.28 ~ 6% +542.9% 316.82 ~ 7% TOTAL iostat.sdc.rkB/s 53.30 ~ 6% +498.9% 319.26 ~ 7% TOTAL iostat.sdf.rkB/s 12.62 ~ 5% +496.4% 75.27 ~ 6% TOTAL iostat.sdg.rrqm/s 53.21 ~ 5% +496.2% 317.20 ~ 6% TOTAL iostat.sdg.rkB/s 12.37 ~ 4% +509.6% 75.41 ~ 7% TOTAL iostat.sdh.rrqm/s 51.89 ~ 4% +511.8% 317.47 ~ 7% TOTAL iostat.sdh.rkB/s 12.60 ~ 5% +500.9% 75.73 ~ 8% TOTAL iostat.sdi.rrqm/s 52.95 ~ 5% +502.2% 318.87 ~ 8% TOTAL iostat.sdi.rkB/s 12.88 ~ 5% +491.9% 76.26 ~ 8% TOTAL iostat.sdj.rrqm/s 54.51 ~ 5% +490.0% 321.59 ~ 8% TOTAL iostat.sdj.rkB/s 12.69 ~ 6% +501.6% 76.35 ~ 8% TOTAL iostat.sdk.rrqm/s 53.90 ~ 6% +497.5% 322.02 ~ 8% TOTAL iostat.sdk.rkB/s 12.69 ~ 5% +501.4% 76.33 ~ 8% TOTAL iostat.sdl.rrqm/s 53.93 ~ 5% +497.4% 322.15 ~ 8% TOTAL iostat.sdl.rkB/s 50.24 ~ 4% +536.4% 319.69 ~ 8% TOTAL iostat.sdb.rkB/s 11.94 ~ 4% +535.0% 75.84 ~ 8% TOTAL iostat.sdb.rrqm/s 11.70 ~ 6% +542.7% 75.21 ~ 7% TOTAL iostat.sdc.rrqm/s 12.68 ~ 7% +498.0% 75.82 ~ 7% TOTAL iostat.sdf.rrqm/s 332 ~ 0% +41.9% 471 ~ 0% TOTAL iostat.md0.avgrq-sz 3616709 ~ 1% -28.9% 2573038 ~ 1% TOTAL perf-stat.context-switches 51043 ~ 1% +10.4% 56342 ~ 3% TOTAL perf-stat.cpu-migrations 6.45e+11 ~ 0% -6.7% 6.021e+11 ~ 0% TOTAL perf-stat.dTLB-loads 758 ~ 0% -5.9% 713 ~ 0% TOTAL iostat.md0.w/s Legend: ~XX% - stddev percent [+-]XX% - change percent Disclaimer: Results have been estimated based on internal Intel analysis and are provided for informational purposes only. Any difference in system hardware or software design or configuration may affect actual performance. Thanks, Jet

mdadm -q --create /dev/md0 --chunk=256 --level=raid5 --raid-devices=11 --force --assume-clean /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1 /dev/sdi1 /dev/sdj1 /dev/sdk1 /dev/sdl1 echo 1 > /sys/kernel/debug/tracing/events/writeback/balance_dirty_pages/enable echo 1 > /sys/kernel/debug/tracing/events/writeback/bdi_dirty_ratelimit/enable echo 1 > /sys/kernel/debug/tracing/events/writeback/global_dirty_state/enable echo 1 > /sys/kernel/debug/tracing/events/writeback/writeback_single_inode/enable mkfs -t ext4 -q /dev/md0 mount -t ext4 /dev/md0 /fs/md0 dd if=/dev/zero of=/fs/md0/zero-1 status=none & sleep 600 killall -9 dd