Date: Sun, 14 Mar 1999 22:31:55 -0600 (CST) From: Chris Dillon <cdillon@wolves.k12.mo.us> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: cvs commit: src/sys/cam cam_xpt.c Message-ID: <Pine.BSF.4.05.9903142016270.3847-100000@duey.wolves.k12.mo.us> In-Reply-To: <19990314201946.00024@uriah.heep.sax.de>
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On Sun, 14 Mar 1999, J Wunsch wrote:
> As Jean-Marc Zucconi wrote:
>
> > Yes this is very poor for a wide drive. On my narrow DCAS-34330:
> > Writing the 250 Megabyte file, 'iozone.tmp'...80.351562 seconds
> > Reading the file...38.601562 seconds
> >
> > IOZONE performance measurements:
> > 3262463 bytes/second for writing the file
> > 6791020 bytes/second for reading the file
>
> I get about 4.4 MB/s writing and 5.8 MB/s reading, with tagged queuing
> still enabled. I also get better bonnie figures than those mentioned
> in PR kern/10398, about 4 MB/s `Per Char' and 5 MB/s `Block'.
>
> However, as Ken already mentioned, see the audit-trail from PR 10398
> for a counterexample.
I just did some tests with tagging totally disabled, enabled, and with
only 2 tags. This is long. Sorry in advance for the messy wrapping.
Hopefully everybody can parse it...
da1 at ncr0 bus 0 target 1 lun 0
da1: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit)
da1: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
da0 at ncr0 bus 0 target 0 lun 0
da0: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit)
da0: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
Without tagged queueing - single drive:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4742 96.0 7154 47.3 2540 20.1 5739 95.7 7422 30.2
91.7 4.4
IOZONE performance measurements:
6816542 bytes/second for writing the file
7593647 bytes/second for reading the file
Without tagged queueing - 64 block striped ccd partition:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4499 95.5 9556 86.6 3383 30.5 5537 93.8 12330 65.7
133.9 6.6
IOZONE performance measurements:
6629672 bytes/second for writing the file
11590477 bytes/second for reading the file
da0 at ncr0 bus 0 target 0 lun 0
da0: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged
Queueing Enabled
da0: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
da1 at ncr0 bus 0 target 1 lun 0
da1: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged
Queueing Enabled
da1: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
With tagged queueing - single drive:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4883 97.0 4103 25.8 2263 23.6 5789 95.8 7420 32.4
99.6 4.8
IOZONE performance measurements:
6839119 bytes/second for writing the file
7425600 bytes/second for reading the file
With tagged queueing - 64 block striped ccd partition:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4570 96.2 6725 55.1 2534 23.0 5575 94.0 11776 65.2
148.3 7.5
IOZONE performance measurements:
6687480 bytes/second for writing the file
11481413 bytes/second for reading the file
da0 at ncr0 bus 0 target 0 lun 0
da0: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged
Queueing Enabled
da0: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
da1 at ncr0 bus 0 target 1 lun 0
da1: <IBM DCAS-34330W S65A> Fixed Direct Access SCSI-2 device
da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged
Queueing Enabled
da1: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
With tagged queueing (min/max 2 tags) - single drive:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4882 97.1 6961 46.4 2897 24.1 5761 95.6 7427 32.7
100.9 4.6
IOZONE performance measurements:
6759895 bytes/second for writing the file
7600097 bytes/second for reading the file
With tagged queueing (min/max 2 tags) - 64 block striped ccd
partition:
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
200 4562 96.5 9323 86.9 3275 30.4 5663 95.1 12382 68.4
143.2 7.1
IOZONE performance measurements:
6603578 bytes/second for writing the file
11226911 bytes/second for reading the file
By these measurements, completely turning off tagging helped certain
write scenarios and hurt others. You'll notice, however, 2 tags
gained almost as much performance increase as disabling them totally,
and didn't hurt the other scenarios as much. 2 tags may not be
be the optimal selection... its just a starting point that I used,
after noticing some Seagate drives had similar quirks.
-- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net
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