On Tue, Dec 06, 2011 at 11:39:57AM +0100, Bostjan Skufca wrote:
> Random write test?
Sure.
That corsair was giving me /terrible/ write performance, pulled the
intel SSD out of my other machine (unregistered the cache from the
backing device and attached the new SSD all without unmounting the
filesystem :)
Write performance with the intel is not /awesome/, but much more
reasonable:
root@utumno:/mnt# perf record -afg fio ~/rw4k
randwrite: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=64
fio 1.59
Starting 1 process
Jobs: 1 (f=1): [w] [100.0% done] [0K/98365K /s] [0 /24.2K iops] [eta 00m:00s]
randwrite: (groupid=0, jobs=1): err= 0: pid=1560
write: io=16384MB, bw=89547KB/s, iops=22386 , runt=187359msec
cpu : usr=3.94%, sys=14.82%, ctx=300435, majf=0, minf=19
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0%
issued r/w/d: total=0/4194367/0, short=0/0/0
Run status group 0 (all jobs):
WRITE: io=16384MB, aggrb=89547KB/s, minb=91696KB/s, maxb=91696KB/s, mint=187359msec, maxt=187359msec
Disk stats (read/write):
bcache0: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00%
8.97% fio fio [.] 0xd1b2
1.64% fio [kernel.kallsyms] [k] bio_insert <- first bcache function
1.56% fio [kernel.kallsyms] [k] __blockdev_direct_IO
1.24% kworker/1:2 [kernel.kallsyms] [k] __bset_search
1.24% kworker/0:0 [kernel.kallsyms] [k] __bset_search
1.19% swapper [kernel.kallsyms] [k] ahci_interrupt
1.17% kworker/0:1 [kernel.kallsyms] [k] __bset_search
1.17% kworker/1:0 [kernel.kallsyms] [k] __bset_search
1.09% fio [kernel.kallsyms] [k] system_call
1.06% kworker/0:2 [kernel.kallsyms] [k] __bset_search
1.06% kworker/1:1 [kernel.kallsyms] [k] __bset_search
1.04% fio [kernel.kallsyms] [k] ext4_ext_find_extent
0.96% fio [kernel.kallsyms] [k] _raw_spin_lock_irq
0.92% fio [kernel.kallsyms] [k] bcache_make_request
0.87% swapper [kernel.kallsyms] [k] _raw_spin_lock_irqsave
0.85% swapper [kernel.kallsyms] [k] mwait_idle
0.83% fio [kernel.kallsyms] [k] do_io_submit
0.77% fio [kernel.kallsyms] [k] memset
0.70% fio [kernel.kallsyms] [k] kmem_cache_alloc
0.65% fio [kernel.kallsyms] [k] md5_transform
0.63% fio [kernel.kallsyms] [k] _raw_spin_lock_irqsave
0.61% fio [kernel.kallsyms] [k] _raw_spin_lock
0.58% fio [kernel.kallsyms] [k] generic_make_request
0.57% fio libaio.so.1.0.1 [.] 0x6b7
0.50% fio [kernel.kallsyms] [k] gup_pte_range
haven't seen bio_insert() show up that high in a profile before, wonder
what's up with that..
Reran the random read benchmark with the intel:
root@utumno:/mnt# perf record -afg fio ~/rw4k
randwrite: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=64
fio 1.59
Starting 1 process
Jobs: 1 (f=1): [r] [100.0% done] [190.9M/0K /s] [47.7K/0 iops] [eta 00m:00s]
randwrite: (groupid=0, jobs=1): err= 0: pid=1575
read : io=16384MB, bw=153120KB/s, iops=38279 , runt=109571msec
cpu : usr=7.22%, sys=52.15%, ctx=678086, majf=0, minf=85
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0%
issued r/w/d: total=4194367/0/0, short=0/0/0
Run status group 0 (all jobs):
READ: io=16384MB, aggrb=153119KB/s, minb=156794KB/s, maxb=156794KB/s, mint=109571msec, maxt=109571msec
Disk stats (read/write):
bcache0: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00%
Basically, whatever hardware you have bcache will easily max it out.
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