Re: [ircu-development] Slow on high-MTU (local host) connections?

From: Carlo Wood (carlo@alinoe.com)
Date: Tue Nov 06 2001 - 22:35:54 EST

The examples in the previous mail are from the case with MTU is 8000
(and were to only two occurances of a EAGAIN for read() actually).

Allow me show the statistics for both MTU's:

MTU 16436:

~>grep -B1 '\[srvx2\] select.*<0\.[1-9]' mtu16436 | grep '\[srvx2\] read' | wc --lines
    323
~>grep -B1 '\[srvx2\] select.*<0\.[1-9]' mtu16436 | grep '\[srvx2\] read.*EAGAIN' | wc --lines
    323

Conclusion: ALL calls to select() that took longer than 0.1 second
were following a call to read() that failed with EAGAIN. In total 323 times.

MTU 8000:

~>grep -B1 '\[srvx2\] select.*<0\.[1-9]' mtu8000 | grep '\[srvx2\] read' | wc --lines
      2
~>grep -B1 '\[srvx2\] select.*<0\.[1-9]' mtu8000 | grep '\[srvx2\] read.*EAGAIN' | wc --lines
      2

Idem, but only two occurences.

The total number of calls to select in both are respectively:

~>grep '\[srvx2\] select.*' mtu16436 | wc --lines
   1221
~>grep '\[srvx2\] select.*' mtu8000 | wc --lines
   658 

-- 
Carlo Wood <carlo@alinoe.com>

(Also forwarded because first I used a wrong address)
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This archive was generated by hypermail 2b29 : Wed Nov 07 2001 - 21:00:33 EST