forgot to attach lspci output.
it is a 133MB PCI-X card but only run at 66MHZ.
quick question, where I can check if it is running at 64bit?
66MHZ * 32Bit /8 * 80% bus utilization ~= 211MB/s then match the upper
speed I meet now...
Ming
02:01.0 SCSI storage controller: Marvell MV88SX5081 8-port SATA I PCI-X
Controller (rev 03)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop-
ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66Mhz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 128, Cache Line Size 08
Interrupt: pin A routed to IRQ 24
Region 0: Memory at fa000000 (64-bit, non-prefetchable)
Capabilities: [40] Power Management version 2
Flags: PMEClk+ DSI- D1- D2- AuxCurrent=0mA PME
(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [50] Message Signalled Interrupts: 64bit+
Queue=0/0 Enable-
Address: 0000000000000000 Data: 0000
Capabilities: [60] PCI-X non-bridge device.
Command: DPERE- ERO- RBC=0 OST=3
Status: Bus=2 Dev=1 Func=0 64bit+ 133MHz+ SCD- USC-,
DC=simple, DMMRBC=0, DMOST=3, DMCRS=0, RSCEM-
On Wed, 2005-08-31 at 14:52 -0400, Ming Zhang wrote:
> join the party. ;)
>
> 8 400GB SATA disk on same Marvel 8 port PCIX-133 card. P4 CPU.
> Supermicro SCT board.
>
> # cat /proc/mdstat
> Personalities : [linear] [raid0] [raid1] [raid5] [multipath] [raid6]
> [raid10] [faulty]
> md0 : active raid0 sdh[7] sdg[6] sdf[5] sde[4] sdd[3] sdc[2] sdb[1] sda
> [0]
> 3125690368 blocks 64k chunks
>
> 8 DISK RAID0 from same slot and card. Stripe size is 512KB.
>
> run oread
>
> # vmstat 1
> procs -----------memory---------- ---swap-- -----io---- --system-- ----
> cpu----
> r b swpd free buff cache si so bi bo in cs us sy
> id wa
> 1 1 0 533216 330424 11004 0 0 7128 1610 1069 77 0 2
> 95 3
> 1 0 0 298464 560828 11004 0 0 230404 0 2595 1389 1
> 23 0 76
> 0 1 0 64736 792248 11004 0 0 231420 0 2648 1342 0
> 26 0 74
> 1 0 0 8948 848416 9696 0 0 229376 0 2638 1337 0
> 29 0 71
> 0 0 0 868896 768 9696 0 0 29696 48 1224 162 0 19
> 73 8
>
> # time ./oread /dev/md0
>
> real 0m6.595s
> user 0m0.004s
> sys 0m0.151s
>
> run dd
>
> # vmstat 1
> procs -----------memory---------- ---swap-- -----io---- --system-- ----
> cpu----
> r b swpd free buff cache si so bi bo in cs us sy
> id wa
> 2 2 0 854008 2932 17108 0 0 7355 1606 1071 80 0 2
> 95 3
> 0 2 0 848888 3112 21388 0 0 164332 0 2985 3564 2
> 7 0 91
> 0 2 0 844024 3260 25664 0 0 164040 0 2990 3665 1
> 7 0 92
> 0 2 0 840328 3380 28920 0 0 164272 0 2932 3791 1
> 9 0 90
> 0 2 0 836360 3500 32232 0 0 163688 100 3001 5045 2
> 7 0 91
> 0 2 0 831432 3644 36612 0 0 164120 568 2977 3843 0
> 9 0 91
> 0 1 0 826056 3752 41688 0 0 7872 0 1267 1474 1 3
> 0 96
>
> # time dd if=/dev/md0 of=/dev/null bs=131072 count=8192
> 8192+0 records in
> 8192+0 records out
>
> real 0m4.771s
> user 0m0.005s
> sys 0m0.973s
>
> so the reasonable thing here is because of O_DIRECT, the sys time
> reduced a lot.
>
> but the time is longer! the reason i found is...
>
> i attached a new oread.c which allow to set block size of each read and
> total read count. so i read full strip once a time,
>
> # time ./oread /dev/md0 524288 2048
>
> real 0m4.950s
> user 0m0.000s
> sys 0m0.131s
>
> compared to
>
> # time ./oread /dev/md0 131072 8192
>
> real 0m6.633s
> user 0m0.002s
> sys 0m0.191s
>
>
> but still, I can get linear speed at 4 DISKS, then no speed gain when
> adding more disk into the RAID.
>
> Ming
>
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