2002-03-25 19:30:59

by Steffen Persvold

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Subject: Network performance i 2.4.18 compared to 2.4.17


Hi folks,

I've developed a network driver ontop of SCI. Now I've detected something
wierd. Network performance, both UDP and TCP, measured with netperf is a
little lower i 2.4.18 than in 2.4.17. The machines I'm running my tests on
is Dual Athlon MP 1900 (1.6 GHz) in a Tyan Tiger MPX (S2566) board. Kernel
configs on both 2.4.17 and 2.4.18 is excactly the same and its configured
with cpu type K7.

Here are the numbers :

2.4.18 kernel :

TCP STREAM TEST to sci5
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. MBytes/sec

524288 524288 524288 9.99 175.87

UDP UNIDIRECTIONAL SEND TEST to sci5
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # MBytes/sec

262144 32768 9.99 63054 0 197.22
262144 9.99 63054 197.22


and on 2.4.17 kernel :

TCP STREAM TEST to sci5
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. MBytes/sec

524288 524288 524288 10.00 182.92

UDP UNIDIRECTIONAL SEND TEST to sci5
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # MBytes/sec

262144 32768 10.00 64359 0 201.20
262144 10.00 64359 201.20


Roughly 2% lower performance on UDP and 4% on TCP. Any explaination for
this ?

Thanks in advance.

Regards,
--
Steffen Persvold | Scalable Linux Systems | Try out the world's best
mailto:[email protected] | http://www.scali.com | performing MPI implementation:
Tel: (+47) 2262 8950 | Olaf Helsets vei 6 | - ScaMPI 1.13.8 -
Fax: (+47) 2262 8951 | N0621 Oslo, NORWAY | >320MBytes/s and <4uS latency