is RTL8139 THAT bad?

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Sun Jun 21 15:16:04 UTC 2009


i have pentium 200 with that card. doing ftp from other machine, getting 
3.5MB/s (HDD can 10MB/s, DMA) having 45%-55% interrupt load.

when sending it's not that bad.

tried writing file to disk with cat /dev/zero >file, it's only 3% ints 
with 10MB/s traffic.


Why it's THAT bad?

3.5MB/s is less that 2500 packets/second. 50% at 200Mhz means 100000000 
cycles spend on interrupt service, which is 40000 CPU cycles per packet.



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