"Richard B. Johnson" <root@chaos.analogic.com>

Manfred Spraul (manfred@colorfullife.com)
Thu, 24 Oct 2002 18:04:30 +0200

>
>
>A 400 MHz ix86 CPU will checksum/copy at 685 megabytes per second.
>It will copy at 1,549 megabytes per second. Those are megaBYTES!
>
>
Interesting. You copy data with 1,549 megabytes per second over a 800
megabytes per second frond side bus, into (probably) PC100 memory, i.e.
theoretical bandwidth of 800 megabytes/sec.
You probably operate within the L2 cache.

Roy, which type of memory and which chipset do you use?
The csum/copy speed is 210 MByte/sec: 13% cpu time needed for 225
mbit/sec. That could be correct, if you use SDRAM and everything is
cache-cold (source dma from disk, dest previously used as a network
buffer, dma from nic)

--
    Manfred




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