john@ticipa.ti.com (John Maline) (06/28/90)
A recent thread here has discussed tuning some parameters in the Adaptec 154x driver in 386/ix. Is there an equivalent set of (administrator accessible) parameters in SCO Unix? I've tried enabling synchronous negotiation and increasing the DMA transfer speed via the on-board jumpers. Neither showed any significant change in my simple benchmark (aside from an I/O error when DMA was set to 8 MB/s). Background: My simple I/O speed test was: time dd if=/dev/root of=/dev/null bs=10240 results: time user sys asynchronous (sync enb jumper off) 7:32.0 0.9 2:17.1 synchronous 7:29.3 1.2 2:09.7 synchronous, DMA=5.7 MB/s 7:29.3 1.0 2:10.1 I interpret these similar results to indicate that SCO's driver overrides the jumpers in software (as the Adaptec 1542a manual implies can be done on p 2-14). This doesn't explain the I/O error at 8MB/s, though... System Configuration: AST 386/33, 10Mb RAM, Adaptec 1542a, Maxtor 4170S, root partn=129397K SCO Open Desktop (Unix V.3.2.1) Any help/info would be greatly appreciated. Regards, John Maline UUCP: john@ticipa@tilde.ti.com Texas Instruments PO Box 655012 M/S 3635 TI MSG: JWMX Dallas, TX 75265 Voice: (214) 917-2245
pcg@cs.aber.ac.uk (Piercarlo Grandi) (07/05/90)
In article <440@ticipa.ti.com> john@ticipa.ti.com (John Maline) writes:
My simple I/O speed test was:
time dd if=/dev/root of=/dev/null bs=10240
results: time user sys
asynchronous (sync enb jumper off) 7:32.0 0.9 2:17.1
synchronous 7:29.3 1.2 2:09.7
synchronous, DMA=5.7 MB/s 7:29.3 1.0 2:10.1
But reading from the block device entails such colossal kernel overheads
for cache management, as duly documented in the sys time, that it is
hard to gauge raw IO bandwidth. On the other hand, 130 megs in 450
seconds comes to 200-300 KB sec., which is like Larry Snyder's results.
--
Piercarlo "Peter" Grandi | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.ukneese@adaptex.UUCP (07/06/90)
>/* ---------- "Adaptec 154x Tuning for SCO Unix" ---------- */ >A recent thread here has discussed tuning some parameters in the Adaptec >154x driver in 386/ix. Is there an equivalent set of (administrator >accessible) parameters in SCO Unix? > >I've tried enabling synchronous negotiation and increasing the DMA >transfer speed via the on-board jumpers. Neither showed any significant >change in my simple benchmark (aside from an I/O error when DMA was set >to 8 MB/s). > >>STUFF DELETED > >I interpret these similar results to indicate that SCO's driver >overrides the jumpers in software (as the Adaptec 1542a manual implies >can be done on p 2-14). This doesn't explain the I/O error at 8MB/s, >though... The SCO driver does override the jumper settings for DMA rate. I beleive you need to patch the variable "aha_xfer" to the value you want. The sync jumper cannot be overridden by software. The reason you cannot run at 8MB/sec is the CPU. The implementation of the memory addressing will not allow the CPU/bus to run that fast. Some systems can run that fast, others cannot. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ uunet!swbatl!texbell! {nominil,merch,cpe,mlite}!adaptex!neese