Re: [PATCH] tcp: Expose the initial RTO via a new sysctl.

Le mardi 17 mai 2011 à 13:02 +0200, Hagen Paul Pfeifer a écrit :

On Tue, 17 May 2011 10:07:57 +0200, Eric Dumazet wrote:

quoted

I wont discuss if introducing a new sysctl is welcomed, only on patch
issues. I believe some work in IETF is done to reduce the 3sec value to
1sec anyway.

Why not? 

Just because I let this point to David and others. I personally dont
care that much.

I though all new knobs in this area should be done on a per route
metric so it can be controlled on a per path basis. RTO should be
adjustable on a per path basis, because it depends on the path.

Adding many knobs to each clone had a huge cost on previous kernels.
(Think some machines have millions entries in IP route cache), this used
quite a lot of memory.

With latest David work, we'll consume less ram, because we can now share
settings, instead of copying them on each dst entry.

Some months back [1] I posted a patch to enable/disable TCP quick ack
mode, which has nothing to do with network paths, just with a local server
policy. But David rejected the patch with the argument that I should use a
per path knob (this is a little bit inapprehensible for me, but David has
the last word).

Well, if nobody speaks after David, he has the last word indeed.

BTW, I remember Stephen actually asked the per route thing, not David.

http://kerneltrap.org/mailarchive/linux-netdev/2010/8/23/6283641

Then David also stated it :

http://kerneltrap.org/mailarchive/linux-netdev/2010/8/23/6283678

If you really want tcp_quickack thing you really should do it as
requested by both Stephen & David ;)

Unfortunately, I dont know if its really needed or worthwhile.