Date: Tue, 12 Mar 2002 16:21:27 -0700 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Eric Dantan Rzewnicki <rzewnickie@rfa.org> Cc: aic7xxx@FreeBSD.ORG Subject: Re: performance issues: linux aic7xxx, 29160, Radion IFT-7200 Message-ID: <200203122321.g2CNLSI37266@aslan.scsiguy.com> In-Reply-To: Your message of "Tue, 12 Mar 2002 18:07:16 EST." <3C8E8A24.30EB6920@rfa.org>
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>"Justin T. Gibbs" wrote: >> >> >Hello again, >> >> I wonder if for some reason we have disconnection disabled? I get much >> better performance than that talking to a plain old 10K RPM disk. Can >> you go into aic7xxx.c, search for ahc->user_discenable and print out the >> contents of that variable? > >linux-2.4.18/drivers/scsi/aic7xxx/aic7xxx.c >(not-patched, so this is version 6.2.4) >line 4547 >ahc->user_discenable = discenable; I meant insert a printf to display the actual value of the variable after it is set. 8-) >same in 2.4.16 ( I guess that's the same version so that would make >sense, of course...) > >after patching the 2.4.18 sources for aic7xxx 6.2.5 the file names in >drivers/scsi/aic7xxx/ are different. Which one should I be looking at >there? aic7xxx_core.c >> >Is there something else I can do to try to get better performance with >> >the new driver? >> >> If I understood why the performance was bad, I'd tell you. 8-) >> Any chance you can rent a SCSI bus analyzer for a day and capture >> some traces? > >umm, I'll check with the boss, but I doubt it. Where would a person rent >such a thing? Check the yellow pages under electronic test equipment rentals. This is the same place you'd go to rent a logic analyzer or scope for a few days. You could also see if Verisys, Ancot, or Innotec, would allow you to "demo" their SCSI analyzer products. >Ok, so probably very few people would ever care only about sequential >performance? We will have up to 4 streams of current broadcasts writing >to disk and potentially 'many' users streaming via http or copying via >http or smb from the archive. And for a time, someone will be copying >the past archives off CDs onto the raid via a samba share. > >Can hdparm be used to measure non-sequential performance? is there a way >to quantify this? hdparam is a very poor benchmark in general. Doug Ledford lists some other benchmarking tools on his web site that might be of interest, but I have never tried them personally. I'm still very perplexed by the difference in performance. Can you also provide a cat of /proc/scsi/aic7xxx/0 <- or whatever bus number happens to have this device on it. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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