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Date:      Thu, 18 Dec 1997 18:35:40 -0500
From:      Brian Campbell <brianc@pobox.com>
To:        multimedia@FreeBSD.ORG
Subject:   Re: 3.0-current plug for IDE DMA -- very nice!
Message-ID:  <19971218183540.63627@pobox.com>
In-Reply-To: <19971217222428.27336@ct.picker.com>; from Randall Hopper on Wed, Dec 17, 1997 at 10:24:28PM -0500
References:  <19971217222428.27336@ct.picker.com>

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On Wed, Dec 17, 1997 at 10:24:28PM -0500, Randall Hopper wrote:
>      Pretty cool.  Upgraded to 3.0-current, flipped some config switches,
> and now we're capturing 30fps 320x240 RGB16 video (w/ full CD-quality
> audio) to EIDE disk with almost no skips -- and on one disk only!
> Kudos to John Hood for his IDE DMA patches last summer.
> 
>      If you've got IDEs, want to grab some MPEGs, and aren't running
> current or a current SNAP right now, let me tell you, this is really the
> way to go.  It blew me away to see it the first time!
> 
>      For those that are interested, on 2.2.1 on my relatively new Western
> Digital AC34300L 4.3Gig EIDE drive:
> 
>           # dd if=/dev/rwd0 of=/dev/null bs=1m count=200
>           209715200 bytes transferred in 33.157129 secs (6324890 bytes/sec)
>                                                          ^^^^^^^
> Now pop in 3.0-971208-SNAP with wdc flags 0xa0ffa004, and we now get:
> 
>           # dd if=/dev/rwd0 of=/dev/null bs=1m count=200
>           209715200 bytes transferred in 22.699848 secs (9238617 bytes/sec)
>                                                          ^^^^^^^

You don't need to run -current to get IDE DMA.  I've been running
John's DMA patches to -stable since this summer and haven't had
any problems.  It'd be nice if they made it into -stable too ...

    # time dd if=/dev/rwd0 of=/dev/null bs=1m count=200
    209715200 bytes transferred in 28.166086 secs (7445664 bytes/sec)
    0.0u 0.3s 0:28.23 1.0% 54+2488k 0+0io 0pf+0w

I think your drive is just faster than mine (WDC AC32500H)   :-(
Although, you probably can get better throughput with PIO

> That's a pretty "respectable" improvement, IMO.  :-)  BTW, this is on a
> P55T2P4 MB w/ P233MMX, 48MB phys w/ 96MB swap.

This is from a P166 (non-MMX), 64M phys, 128M swap



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