Subject: Re: pciide performance on alpha
To: Jason Thorpe <email@example.com>
From: Andreas Johansson <firstname.lastname@example.org>
Date: 08/12/1999 19:49:22
On Thu, 12 Aug 1999, Jason Thorpe wrote:
> Note that the 164SX has a wimpy memory bus speed compared to the 164LX
> and the original PC164 (which had the best of all of them, actually). This
> might contribute.
Please, you are a bit off scale here -- my pciide driver reads about 4MB/s
and a simple memcpy() can copy 108MB/s in my SX. (This actually sucks,
when I tried memcpy() in linux on the same machine, it copied over
> If you get better transfer rates on the *same machine* under a different
> OS (as was implied earlier in the thread, I think), then there may be
> a problem with how we initialize the Cypress controller... but that
Yes, this is what I was saying, I had 7MB/s using my Linux driver, and I
have 3.5MB/s with the NetBSD driver, same machine, same cypress interface.
> would be the only issue; the vast majority of the PCI IDE code is
> shared between all controller types.
The original question was why my newly written Promise driver produces
good performance on i386 but not alpha, and a general alpha problem was
suspected as the Cypress driver also has bad performance. But since the
CMD646 is reported to give expected performance, this seems to be sort of
I guess I'll just have to keep on digging, unless someone else has some
idea what might be wrong.
> -- Jason R. Thorpe <email@example.com>