Having fun testing large data transfers between Mac OS X, Linux 2.6 and Win7 machines.
I was getting very low transfer rate between the Win7 and Linux boxes (12 Mb/s) versus 92 Mb/s for other combinations.
This setting fixed it:
/sbin/sysctl -w net.ipv4.tcp_sack=0
From: http://datatag.web.cern.ch/datatag/howto/tcp.html
SACKs (Selective Acknowledgments) are an optimisation to TCP which in normal scenarios improves considerably performance. In Gigabit networks with no traffic competition these have the opposite effect.But now, I have to figure out why I'm getting less than 100mb/s>
2 comments:
Il y a toujours un overhead (les headers des paquets) sur chaque paquet envoyer sur un network. Tu auras jamais exactement 100Mb/s sur un lien 100Mb.
A moins que tu testais autre chose :).
Le probleme c'est que je suis suppose avoir un reseau 1Gb/s! Mais il se comporte comme un reseau 100 Mb/s...
En fait, 92 Mb/s c'est tres eleve pour un 100 Mb/s...
En connection directe entre les deux ordis, j'ai environ 288 Mb/s.
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