Re: [PATCH] eepro100 - need testers

Tim Hockin (thockin@sun.com)
Thu, 06 Dec 2001 17:05:48 -0800

Jeff Garzik wrote:

> This patch got me thinking about net driver ring sizes in general. When
> you are talking thousands of packets per second at 100 mbit, a larger
> ring size than the average 32-64 seems to make sense too.

Well, the math for teh very worst case is something like:

100,000,000 bits/sec
/8
= 12500000 bytes/sec
/64 bytes/ping
= 195312.5 ping/sec
/100
= 1953 ping/jiffy
rounded to 2048
/2 = 1024 rx buffers per 1/2 jiffie.

1024 means you can withstand a wire-speed storm while interrupting twice
per jiffy.

-- 
Tim Hockin
Systems Software Engineer
Sun Microsystems, Cobalt Server Appliances
thockin@sun.com
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