* "Richard B. Johnson" <root@chaos.analogic.com>
@ 2002-10-24 16:04 Manfred Spraul
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From: Manfred Spraul @ 2002-10-24 16:04 UTC (permalink / raw)
To: Roy Sigurd Karlsbakk, Richard B. Johnson; +Cc: linux-kernel
>
>
>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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2002-10-24 16:04 "Richard B. Johnson" <root@chaos.analogic.com> Manfred Spraul
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