Date: Sat, 24 Jun 2006 00:25:06 +0300 From: Volodymyr Kostyrko <arcade@synergetica.dn.ua> To: "Justin T. Gibbs" <gibbs@scsiguy.com> Cc: freebsd-scsi@freebsd.org Subject: Re: ahd(4) poor performance Message-ID: <449C5C32.1090808@synergetica.dn.ua> In-Reply-To: <0C5F4B7D7A8779025C3E480D@[10.0.0.22]> References: <4499B748.6040805@synergetica.dn.ua> <90D11403BD2140875BFEB24D@[10.0.0.22]> <449C0E34.3080005@synergetica.dn.ua> <5272604BA34A45926DFA0D2F@[10.0.0.22]> <449C1861.3080902@synergetica.dn.ua> <0C5F4B7D7A8779025C3E480D@[10.0.0.22]>
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Justin T. Gibbs wrote:
> Access the raw device to bypass the filesystem and VM subsystem.
> Start N dds where N is the queue depth you've configured for
> the device.
I've made almost the same test on /dev/da0s1b (the swap partition).
Script:
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
dd if=/dev/zero of=/dev/da0s1b count=20480&
wait
> camcontrol tags 0:0 -v
(pass0:ahd0:0:0:0): dev_openings 8
(pass0:ahd0:0:0:0): dev_active 8
(pass0:ahd0:0:0:0): devq_openings 8
(pass0:ahd0:0:0:0): devq_queued 0
(pass0:ahd0:0:0:0): held 0
(pass0:ahd0:0:0:0): mintags 2
(pass0:ahd0:0:0:0): maxtags 255
2 users Load 0.31 0.49 0.49 23 чер 21:13
Mem:KB REAL VIRTUAL VN PAGER SWAP PAGER
Tot Share Tot Share Free in out in out
Act 106680 13672 316112 27816 1624096 count
All 424236 19976 73870680 41352 pages
Interrupts
Proc:r p d s w Csw Trp Sys Int Sof Flt cow 8190 total
9 80 1541 9 553 555 2 144940 wire
4: sio0
83608 act
14: ata
0.0%Sys 0.0%Intr 0.0%User 0.0%Nice 99.9%Idl 197908 inact 3
16: uhc
| | | | | | | | | | 12 cache
19: uhc
1624084 free
20: em1
daefr
23: ehc
Namei Name-cache Dir-cache prcfr 3
32: em0
Calls hits % hits % react 196
66: ahd
4 4 100 pdwak
67: ahd
zfod pdpgs 1997
cpu0: time
Disks da0 da1 pass0 pass1 ozfod intrn 1997
cpu2: time
KB/t 0.50 0.00 0.00 0.00 %slo-z 114464 buf 1997
cpu1: time
tps 195 0 0 0 tfree 51 dirty 1997
cpu3: time
MB/s 0.10 0.00 0.00 0.00 100000 desiredvnodes
% busy 100 0 0 0 7750 numvnodes
6193 freevnodes
Script output is:
20480+0 records in
20480+0 records out
10485760 bytes transferred in 363.641053 secs (28835 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 483.640098 secs (21681 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 483.650721 secs (21680 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 604.895852 secs (17335 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 618.500802 secs (16954 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 618.539979 secs (16952 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 618.545158 secs (16952 bytes/sec)
20480+0 records in
20480+0 records out
10485760 bytes transferred in 618.553915 secs (16952 bytes/sec)
Hmm... My ATA drive does the same almost three times faster...
--
[WBR], Arcade.
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