Date: Tue, 31 Oct 2000 20:12:25 -0800 (PST) From: Tom Samplonius <tom@sdf.com> To: The Hermit Hacker <scrappy@hub.org> Cc: freebsd-scsi@freebsd.org Subject: Re: iostat: tps for SCSI drives ... Message-ID: <Pine.BSF.4.05.10010312006570.24950-100000@misery.sdf.com> In-Reply-To: <Pine.BSF.4.21.0010312020040.494-100000@thelab.hub.org>
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On Tue, 31 Oct 2000, The Hermit Hacker wrote: > Okay, how do I read this: > > pgsql# camcontrol tags da0 -v > (pass0:ahc0:0:0:0): dev_openings 41 > (pass0:ahc0:0:0:0): dev_active 0 > (pass0:ahc0:0:0:0): devq_openings 41 > (pass0:ahc0:0:0:0): devq_queued 0 > (pass0:ahc0:0:0:0): held 0 > (pass0:ahc0:0:0:0): mintags 2 > (pass0:ahc0:0:0:0): maxtags 255 I wonder why dev_openings is lower than maxtags? > pgsql# camcontrol tags da1 -v > (pass1:ahc0:0:1:0): dev_openings 1 > (pass1:ahc0:0:1:0): dev_active 0 > (pass1:ahc0:0:1:0): devq_openings 1 > (pass1:ahc0:0:1:0): devq_queued 0 > (pass1:ahc0:0:1:0): held 0 > (pass1:ahc0:0:1:0): mintags 2 > (pass1:ahc0:0:1:0): maxtags 255 Here dev_openings is 1, so that would mean that the kernel can't have more than one pending command. Since it is a (crappy) Fijitsu drive, I would expect that either the drive told that the kernel it won't queue commands, or there is quirk entry that disables tags for this drive. > pgsql# iostat -n5 -t da 5 > tty da0 da1 da2 cpu > tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id > 77083887 48.00 36 1.67 0.00 0 0.00 0.00 0 0.00 23 0 9 0 68 > 0 9856 42.97 34 1.45 0.00 0 0.00 8.07 23 0.18 0 0 0 0 0 > 0 9856 39.77 41 1.57 0.00 0 0.00 8.00 23 0.18 0 0 0 0 0 > > max/mintags aren't a problem ... I take it, from what I'm reading in the > man page, the 'pending' is the dev_active field? So, there is nothing > pending? > > The two drives in use above are: > > da0 at ahc0 bus 0 target 0 lun 0 > da0: <SEAGATE ST39103LW 0002> Fixed Direct Access SCSI-2 device > da0: 80.000MB/s transfers (40.000MHz, offset 15, 16bit), Tagged Queueing Enabled > da0: 8683MB (17783240 512 byte sectors: 255H 63S/T 1106C) > da2 at ahc0 bus 0 target 2 lun 0 > da2: <FUJITSU MAE3182LP 0112> Fixed Direct Access SCSI-2 device > da2: 80.000MB/s transfers (40.000MHz, offset 63, 16bit), Tagged Queueing Enabled > da2: 17431MB (35700480 512 byte sectors: 255H 63S/T 2222C) > > So, for the Seagate, according to Seagate, the avg seek time is 5.2ms ... > so I should max out around 192.3 tps on that drive? I know, not set in > stone, but a reasonable number to work with, right? And, from what I can > tell about the Fujitso, they are running around 7ms, so ~142tps? > > Does this make sense? > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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