tree e77246acf5defad56ee5feb23be7b3db57e56925
parent ca5ed5b8753e71c15e1acbd753c4fd65cd3813a0
author Jeremy Hylton <jeremy@alum.mit.edu> 1026854471 +0000
committer Jeremy Hylton <jeremy@alum.mit.edu> 1026854471 +0000
HG:extra convert_revision:svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/python/branches/legacy-trunk%4027644

Send HTTP requests with a single send() call instead of many.

The implementation now stores all the lines of the request in a buffer
and makes a single send() call when the request is finished,
specifically when endheaders() is called.

This appears to improve performance.  The old code called send() for
each line.  The sends are all short, so they caused bad interactions
with the Nagle algorithm and delayed acknowledgements.  In simple
tests, the second packet was delayed by 100s of ms.  The second send was
delayed by the Nagle algorithm, waiting for the ack.  The delayed ack
strategy delays the ack in hopes of piggybacking it on a data packet,
but the server won't send any data until it receives the complete
request.

This change minimizes the problem that Nagle + delayed ack will cause
a problem, although a request large enough to be broken into two
packets will still suffer some delay.  Luckily the MSS is large enough
to accomodate most single packets.

XXX Bug fix candidate?