#894 200mS delay on block replies

[Johan Sintorn]

Running Privoxy version 2.0.23 for Windows on Windows Server 2008 R2 Standard I suffer from high latency for all blocked requests when connecting to the proxy from other hosts. The latency is 200 mSec and up. When running locally, latency is less than a mSec.

After some research I realize that the problem most probably is that the the short blocking packets are hit by the Nagle algorithm employed by windows servers. Privoxy should set up its connections with the TCP_NODELAY flag set. Please see https://support.microsoft.com/en-us/kb/214397

I have no means to change the way the sockets are set up from the browser I am testing from, but as latency is a lot better towards other proxies, I am sure the issue can be fixed in the privoxy end.

The problem is easily replicated using firefox. Set up privoxy, configure it to be your proxy, Rightclick on any browsing area and select "Inspect Element". When the new window comes up, select the "network" tab and then switch to the browser and browse to a site that will be blocked by privoxy. The request time is desplayed in the network inspector. If running from another host than where privoxy runs, the response time will be more than 200mS.

[Fabian Keil]

Thanks a lot for the report.

I can reproduce the issue on ElectroBSD where setting the TCP_NODELAY
flag on the accepted socket reduces the latency by 100 ms. Unfortunately
this also seems to unmask a bug that occasionally results in content being
received incompletely, which has to be analyzed and fixed before the
change can be committed.

[Fabian Keil]

This is fixed in CVS now. Thanks again for the report.