On Tue, May 31, 2011 at 09:41, Anupam Kapoor [off-list ref] wrote:

yup, that's what i also think. is it possible that nagle+delayed-ack
is causing the perceived slow-down ?

could be, but have you tried to switch and use various congestion
control ? check /proc/sys/net/ipv4/tcp_congestion_control and here are
enabled ones from my distro stock kernel:
$ grep -i cong /boot/config-`uname -r`
CONFIG_TCP_CONG_ADVANCED=y
CONFIG_TCP_CONG_BIC=y
CONFIG_TCP_CONG_CUBIC=y
CONFIG_TCP_CONG_WESTWOOD=m
CONFIG_TCP_CONG_HTCP=m
CONFIG_TCP_CONG_HSTCP=m
CONFIG_TCP_CONG_HYBLA=m
CONFIG_TCP_CONG_VEGAS=m
CONFIG_TCP_CONG_SCALABLE=m
CONFIG_TCP_CONG_LP=m
CONFIG_TCP_CONG_VENO=m
CONFIG_TCP_CONG_YEAH=m
CONFIG_TCP_CONG_ILLINOIS=m
CONFIG_DEFAULT_TCP_CONG="cubic"

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com