Hi, On 03/10/14 15:16, Julien Charbon wrote: > On 23/05/14 14:06, Julien Charbon wrote: >> On 27/02/14 11:32, Julien Charbon wrote: >>> On 07/11/13 14:55, Julien Charbon wrote: >>>> On Mon, 04 Nov 2013 22:21:04 +0100, Julien Charbon >>>> <jchar...@verisign.com> wrote: >>>>> I have put technical and how-to-repeat details in below PR: >>>>> >>>>> kern/183659: TCP stack lock contention with short-lived connections >>>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=183659 >>>>> >>>>> We are currently working on this performance improvement effort; it >>>>> will impact only the TCP locking strategy not the TCP stack logic >>>>> itself. We will share on freebsd-net the patches we made for >>>>> reviewing and improvement propositions; anyway this change might also >>>>> require enough eyeballs to avoid tricky race conditions introduction >>>>> in TCP stack.
As usual, a follow-up the TCP short-lived connections performance improvement progress: Thanks to jhb (mentor/reviewer) and adrian, rpaulo, rwatson (reviewers), two related commits have been added in HEAD: - First, just a fix for a wrong ECONNRESET error on close(): A connection in TIME_WAIT state before calling close() actually did not received any RST packet https://svnweb.freebsd.org/base?view=revision&revision=273014 - Second, a race condition fix with a code clean-up: Fix a race condition in TCP timewait between tcp_tw_2msl_reuse() and tcp_tw_2msl_scan() https://svnweb.freebsd.org/base?view=revision&revision=273850 It means that the whole set of tcp_tw_2msl_scan()-related changes could now be MFC-ed in 10-STABLE as the KBI stability can be kept now: https://svnweb.freebsd.org/base?view=revision&revision=264321 https://svnweb.freebsd.org/base?view=revision&revision=264342 https://svnweb.freebsd.org/base?view=revision&revision=264351 https://svnweb.freebsd.org/base?view=revision&revision=264356 https://svnweb.freebsd.org/base?view=revision&revision=273850 It also means that only one (big) related patch remains to be pushed: Introduce the INP_LIST global mutex for protecting pcbinfo global structures. Then use INP_INFO_RLOCK in critical paths to increase TCP processing scalability, and use INP_INFO_WLOCK in full INPs iteration loops. (See also joined patch). https://github.com/verisign/freebsd/commit/6e47f726f4d58f986e977fb0f816b8a271804460 Nothing new here, just check previous emails in this thread to get all details. So far, we are adding comments and reviewing the change in more specific cases, then we plan to push this change in review around December 2014. My 2 cents. -- Julien
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