544986 - Option to control the TCP receive buffer

Status: RESOLVED FIXED

(Core :: Networking, enhancement)

Description

[bbsh]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a1pre) Gecko/20100201 Minefield/3.7a1pre Firefox/3.7
Build Identifier: 

In bug 454990 a preference was added to control the TCP send buffer size. An option to control the receive one would be useful too. On Vista and 7 this is less needed, but on XP the default buffer usually is under 32KB, which is too small.

Chromium sets the buffer to 64KB if the OS version is XP, otherwise leaves it unchanged. If the latency is high enough, this causes a massive speedup.

Implementing this would be very easy, it's the same thing but using PR_SockOpt_RecvBufferSize instead of PR_SockOpt_SendBufferSize.

The best way to do this though is having a preference value of "-1" mean "autodetect" (for example 128K in XP, don't set on Vista), "0" to disable and any other value to set manually.

Reproducible: Always

Comment 1

[Patrick McManus [:mcmanus]]

hardcoding this means we don't autotune

Comment 2

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=864f7b7e4935

Comment 3

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=38267fd80b04

Comment 4

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=3d431ba9895a

Comment 5

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=3a4d0281e762

Comment 6

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=664d6bdfb391

Comment 7

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=23dc83cf0773

Comment 8

[Patrick McManus [:mcmanus]]

Attachment: [PATCH] - 64KB rwin for windows xp

From c2a4808fd4564172fe6fa8ad6612d41dfd320082 Mon Sep 17 00:00:00 2001
---
 netwerk/base/nsSocketTransport2.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comment 9

[Patrick McManus [:mcmanus]]

so xp doesn't autotune, and by default it doesn't windowscale on the client. It chooses rwin according to what it thinks the link speed is.

so I think the best we're going to do is chrome compat, which is basically check the established rwin, and if its less than 64KB (no scale), bump it up to 64KB. No need to make that an option

Comment 10

[Patrick McManus [:mcmanus]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=a3b09952acce

Comment 11

[Patrick McManus [:mcmanus]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4e8aeef62ee6149bf933dcea38243a2228e0ca1e
Bug 544986 - 64KB rwin for windows xp r=dragana

Comment 12

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/4e8aeef62ee6