Network performance i 2.4.18 compared to 2.4.17

[Steffen Persvold]

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:[e-mail] |  http://www.scali.com  | performing MPI implementation:
Tel: [phone] |   Olaf Helsets vei 6   |      - ScaMPI 1.13.8 -
Fax: [phone] |   N0621 Oslo, NORWAY   | >320MBytes/s and <4uS latency