On 09/13/12 13:13, Garrett Cooper wrote:
On Thu, Sep 13, 2012 at 12:54 PM, matt <sendtom...@gmail.com> wrote:
On 09/10/12 19:31, Garrett Cooper wrote:
...

It seems hw.mfi.max_cmds is read only. The performance is pretty close to
expected with no nvram or bbu on this card and commodity disks from 1.5
years ago, as far as I'm concerned. I'd love better write performance, but
it's probably being held back by the single platter in the mirror when it is
writing far from its edge.
Try loader.conf:

$ grep -r hw.mfi.max_cmds /sys/dev/mfi/
/sys/dev/mfi/mfi.c:TUNABLE_INT("hw.mfi.max_cmds", &mfi_max_cmds);

Cheers,
-Garrett
Here are the results for differing values of max_cmds with same test conditions as against mps

Original mfi performance (max_cmds=128)

Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP flatline.local 32G 125 99 71443 24 53177 21 317 99 220280 33 255.3 52
Latency               533ms     566ms    1134ms   86565us 357ms     252ms
Version 1.96 ------Sequential Create------ --------Random Create-------- flatline.local -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 22347 94 12389 30 16804 100 18729 99 27798 99 5317 99
Latency             33818us     233ms     558us   26581us 75us   12319us
1.96,1.96,flatline.local,1,1347329123,32G,,125,99,71443,24,53177,21,317,99,220280,33,255.3,52,16,,,,,22347,94,12389,30,16804,100,18729,99,27798,99,5317,99,533ms,566ms,1134ms,86565us,357ms,252ms,33818us,233ms,558us,26581us,75us,12319us

max_cmds=256

Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP flatline.local 32G 125 99 70856 24 53503 21 327 98 232650 33 265.1 60
Latency               637ms     522ms    1050ms     121ms 318ms     339ms
Version 1.96 ------Sequential Create------ --------Random Create-------- flatline.local -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 17126 76 11865 31 17134 99 18265 99 27169 100 5006 99
Latency               114ms     522ms     875us   24250us 87us   14324us
1.96,1.96,flatline.local,1,1347580235,32G,,125,99,70856,24,53503,21,327,98,232650,33,265.1,60,16,,,,,17126,76,11865,31,17134,99,18265,99,27169,100,5006,99,637ms,522ms,1050ms,121ms,318ms,339ms,114ms,522ms,875us,24250us,87us,14324us

max_cmds=64

Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP flatline.local 32G 125 99 71161 24 54035 21 288 90 229860 34 254.2 62
Latency               310ms     378ms     809ms     567ms 308ms     447ms
Version 1.96 ------Sequential Create------ --------Random Create-------- flatline.local -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 22570 95 14243 35 13170 99 23503 99 +++++ +++ 22225 99
Latency             18111us     282ms    1165us   24786us 117us      80us
1.96,1.96,flatline.local,1,1347584224,32G,,125,99,71161,24,54035,21,288,90,229860,34,254.2,62,16,,,,,22570,95,14243,35,13170,99,23503,99,+++++,+++,22225,99,310ms,378ms,809ms,567ms,308ms,447ms,18111us,282ms,1165us,24786us,117us,80us

Still digesting the differences, but 256 seems to get more random seeks and better sequential reads at the expense of higher latencies (some probably identical). I think with lots of small files like a buildworld, it looks like 64 would excel slightly more than 128, but the differences between 128 and 64 are less extreme than the difference between 128 and 256. Interestingly, sequential read appears better at 64 and 256 than 128, but I assume this is a testing fluke...sample set is small.

Matt
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