Re: [ANNOUNCE] Dolphin PCI-SCI RPM Drivers 1.1-4 released

[Todd]

folx,

i must be missing something here.  i'm not aware of a PCI bus that only
supports 70 MBps but i am probably ignorant.  this is why i was confused
by jeff's performance numbers.  33MHz 32-bit PCI busses should do around
120MB/s (just do the math 33*32/8 allowing for some overhead of PCI bus
negotiation), much greater than the numbers jeff is reporting.  66 MHz
64bit busses should do on the order of 500MB/s.

the performance numbers that jeff is reporting are not very impressive
even for the slowest PCI bus.  we're seeing 993 Mbps (124MB/s) using the
alteon acenic gig-e cards on 32-bit cards on a 66MHz bus.  i would expect
to get somewhat slower on a 33MHz bus but not catastrophically so
(certainly nothing as slow as 60MB/s or 480Mb/s).

what am i misunderstanding here?

todd

On Mon, 29 Jan 2001, Jeff V. Merkey wrote:

> Date: Mon, 29 Jan 2001 16:49:53 -0700
> From: Jeff V. Merkey <[e-mail]>
> To: [e-mail]
> Cc: [e-mail]
> Subject: Re: [ANNOUNCE] Dolphin PCI-SCI RPM Drivers 1.1-4 released
>
>
> Relative to some performance questions folks have asked, the SCI
> adapters are limited by PCI bus speeds.  If your system supports
> 64-bit PCI you get much higher numbers.  If you have a system
> that supports 100+ Megabyte/second PCI throughput, the SCI
> adapters will exploit it.
>
> This test was performed in on a 32-bit PCI system with a PCI bus
> architecture that's limited to 70 MB/S.
>
> Jeff
>
> -
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Todd Underwood, [e-mail]

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