Replying to Slawa Olhovchenkov:
> Щаззз. Где ты столько пакетов на гигабите найдешь? Там и 2М нету.
Ты прав. Облажался :((( У самого гигабита нет, ориентируюсь плохо ...
ftp://robur.slu.se/pub/Linux/net-development/NAPI/converting-to-NAPI.txt
HISTORY:
February 10/2002 -- revision 0.2:
some spell checking ;->
January 12/2002 -- revision 0.1
This is still work in progress so may change.
To keep up to date please watch this space.
Introduction to NAPI
====================
NAPI is a proven (www.cyberus.ca/~hadi/usenix-paper.tgz) technique
to improve network performance on Linux. For more details please
read that paper.
NAPI provides a "inherent mitigation" which is bound by system capacity
as can be seen from the following data collected by Robert on Gigabit
ethernet (e1000):
Psize Ipps Tput Rxint Txint Done Ndone
---------------------------------------------------------------
60 890000 409362 17 27622 7 6823
128 758150 464364 21 9301 10 7738
256 445632 774646 42 15507 21 12906
512 232666 994445 241292 19147 241192 1062
1024 119061 1000003 872519 19258 872511 0
1440 85193 1000003 946576 19505 946569 0
Legend:
"Ipps" stands for input packets per second.
"Tput" == packets out of total 1M that made it out.
"txint" == transmit completion interrupts seen
"Done" == The number of times that the poll() managed to pull all
packets out of the rx ring. Note from this that the lower the
load the more we could clean up the rxring
"Ndone" == is the converse of "Done". Note again, that the higher
the load the more times we couldnt clean up the rxring.
Observe that:
when the NIC receives 890Kpackets/sec only 17 rx interrupts are generated.
The system cant handle the processing at 1 interrupt/packet at that load level.
At lower rates on the other hand, rx interrupts go up and therefore the
interrupt/packet ratio goes up (as observable from that table). So there is
possibility that under low enough input, you get one poll call for each
input packet caused by a single interrupt each time. And if the system
cant handle interrupt per packet ratio of 1, then it will just have to
chug along ....
Остальное я вырезал, там идут технические детали - многим они покажутся
неинтересными ...
--
Paul P 'Stingray' Komkoff 'Greatest' Jr // (icq)23200764 // (irc)Spacebar
PPKJ1-RIPE // (smtp)i@stingr.net // (http)stingr.net // (pgp)0xA4B4ECA4
=============================================================================
"inet-admins" Internet access mailing list. Maintained by East Connection ISP.
Mail "unsubscribe inet-admins" to Majordomo@info.east.ru if you want to quit.
Archive is accessible on
