[lug] RH Linux download + hdparm

[Greg Horne]

DMA = 0
Timing buffered disk reads:  64 MB in 13.35 seconds = 4.79 MB/sec
DMA = 1
Timing buffered disk reads:  64 MB in  6.75 seconds = 9.48 MB/sec

Major improvment on my K6!  Slowed down the Pentium 200 by 1.07 MB/sec.  
Does the DMA setting stay after running hdparm or do I have to make it 
permanent elsewhere?  Thanks for all the info Calvin!

Greg


>From: Calvin Dodge <caldodge at fpcc.net>
>Reply-To: lug at lug.boulder.co.us
>To: lug at lug.boulder.co.us
>Subject: Re: [lug] RH Linux download + hdparm
>Date: Wed, 17 Oct 2001 13:44:29 -0600
>
>On Wed, Oct 17, 2001 at 06:58:00PM +0000, Greg Horne wrote:
> > So I noticed the command 'hdparm' in the previous e-mailand decided to 
>play
> > around.  Boy is that fun!  Testing read speeds on different drives gave 
>me
> > some interesting information.
> >
> > Pentium 200 2.5 gig hard drive (RH 7.0)
> > 'hdparm -t' = 4.83 MB/sec
> >
> > K6 500 10 gig hard drive (RH 6.2)
> > 'hdparm -t' = 3.83 to 4.6 MB/sec
> >
> > Do the different distros on them make any differece?  Do the hard drive
> > brands play a big role in this?  Are there any safe tweaks to speed up
> > access times?
>
>There are supposedly a number of tweaks (invoking various UDMA methods, 
>changing the default read count, etc.), but the only one I've found to 1) 
>make a difference and 2) be relatively safe (YMMV) is enabling DMA (the 
>latest Red Hat kernels do this automatically).
>
>Try "hdparm -d 1 /dev/hda", then see if that makes any difference in the 
>transfer rate. I suspect you'll see a significant difference with your K6. 
>I also suspect you'll see little difference with the P-200.
>
>I don't know about different distros (I'm pretty much a Red Hat guy (not to 
>be confused with the "red guy" from Steve Martin's "Writing Is Easy")), but 
>in general it seems that the newer kernel versions understand more chipsets 
>(like that difference between the 2.4.7 and 2.4.9 kernels).
>
>The drives do make a difference - Mom's 500 Mhz K6-based system (with a 
>Tyan S1598 motherboard) has a 5 gig Micropolis and a 30 gig IBM.  The 
>Micropolis maxes out at about 4 megs/second, while the IBM (a 5400 RPM 
>model) does about 16-17 megs/second.
>
>The same model IBM in our old work server (a P-133 with a 430 TX chipset) 
>transfers at about 8 megs a second - there I think it's obvious that the 
>IDE controller is the bottleneck.
>
>IIRC, with DMA off the IBM drive ran at about 4-5 megs/second (regardless 
>of CPU speed or board age).
>
>And - as mentioned before - the 5400 RPM Maxtor drives on our new work 
>server show about 32-33 megs/second (yes, they're connected with those 
>fancy new 80-wire IDE ribbon cables).
>
>I hope that's enough data (without boring the people who already know all 
>of this).
>
>Calvin
>
>--
>Calvin Dodge
>Certified Linux Bigot (tm)
>http://www.caldodge.fpcc.net
>_______________________________________________
>Web Page:  http://lug.boulder.co.us
>Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug


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