Poor write performance with LSI 320-2 on 6.1-STABLE

[Albert Chin]

On Thu, Sep 28, 2006 at 05:15:05PM -0500, Albert Chin wrote:
> I have an Intel S875PWP1 motherboard with a Pentium4 CPU at 2.40GHz. PCI
> bus is 33Mhz, 32-bit. I recently purchased an LSI 320-2/128MB on eBay
> (though the card really looks like a PERC4/DS) and just ran some
> bonnie++ tests on a RAID 1 array between two U320 drives for the first
> channel and on a RAID 0 array between one U320 drive for the second
> channel. The 320-2 has the latest LSI firmware, 1L47.

I reran some of the tests with the same 320-2 but on an Intel
SE7520BD2 with 32-bit and 64-bit (100Mhz) slots:
  #1. RAID 1, two U320 drives, channel 1, 32-bit, 33Mhz slot
Version 1.93c       ------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
maetel.il.thew 300M   186  99 16707   5 16063   6   654  99 537320  93  4129  50
Latency             45215us     199ms   89764us   34740us    1215us    1808ms
Version 1.93c       ------Sequential Create------ --------Random Create--------
maetel.il.thewritte -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  7441  23 +++++ +++ +++++ +++  5799  18 +++++ +++ +++++ +++
Latency               479ms     122us    2508us     606ms   13549us     101us

  #2. RAID 1, two U320 drives, channel 1, 64-bit, 100Mhz slot
Version 1.93c       ------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
maetel.il.thew 300M   186  99 18006   6 15964   5   634  99 571275  99  4450  57
Latency             44992us     139ms     130ms   35143us    1238us     120ms
Version 1.93c       ------Sequential Create------ --------Random Create--------
maetel.il.thewritte -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  7581  24 +++++ +++ +++++ +++  5750  18 +++++ +++ +++++ +++
Latency               511ms     255us    2615us     622ms   12691us      53us

Odd that I don't get x2 the performance when the bus bandwidth doubles
in speed.

With the write policy set to "write-back", performance increases to:
  #3. RAID 1, two U320 drives, channel 1, 32-bit, 33Mhz slot
Version 1.93c       ------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
maetel.il.thew 300M   182  99 36466  12 28602  11   624  97 570155  99 +++++ +++
Latency               102ms     918ms    1739ms   35305us    1210us     198ms
Version 1.93c       ------Sequential Create------ --------Random Create--------
maetel.il.thewritte -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 18283  57 +++++ +++ +++++ +++ 16092  50 +++++ +++ +++++ +++
Latency             65371us     107us     101us     119ms     258us     104us

  #4. RAID 1, two U320 drives, channel 1, 64-bit, 100Mhz slot
Version 1.93c       ------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
maetel.il.thew 300M   186  99 43215  14 35049  12   560  88 569643  99 +++++ +++
Latency             44935us    2071ms    1174ms   35558us    1213us     279ms
Version 1.93c       ------Sequential Create------ --------Random Create--------
maetel.il.thewritte -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 19689  62 +++++ +++ +++++ +++ 15578  51 +++++ +++ +++++ +++
Latency             67923us    1227us   49362us     117ms     198us      93us

-- 
albert chin (china at thewrittenword.com)