Date: Fri, 23 Jun 2006 17:17:53 -0600 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Volodymyr Kostyrko <arcade@synergetica.dn.ua> Cc: freebsd-scsi@freebsd.org Subject: Re: ahd(4) poor performance Message-ID: <A864B70F5AEEAEA7CA8EE57A@[10.0.0.22]> In-Reply-To: <449C5C32.1090808@synergetica.dn.ua> 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]> <449C5C32.1090808@synergetica.dn.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
Enable the write cache on your scsi disk or disable it on your ata disk. -- Justin --On Saturday, June 24, 2006 12:25 AM +0300 Volodymyr Kostyrko <arcade@synergetica.dn.ua> wrote: > 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 ??? 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. >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?A864B70F5AEEAEA7CA8EE57A>