From owner-svn-src-all@FreeBSD.ORG Wed Oct 9 12:00:38 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id E9027B00; Wed, 9 Oct 2013 12:00:38 +0000 (UTC) (envelope-from glebius@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id D6F8E2110; Wed, 9 Oct 2013 12:00:38 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.7/8.14.7) with ESMTP id r99C0cGW039542; Wed, 9 Oct 2013 12:00:38 GMT (envelope-from glebius@svn.freebsd.org) Received: (from glebius@localhost) by svn.freebsd.org (8.14.7/8.14.5/Submit) id r99C0cLR039540; Wed, 9 Oct 2013 12:00:38 GMT (envelope-from glebius@svn.freebsd.org) Message-Id: <201310091200.r99C0cLR039540@svn.freebsd.org> From: Gleb Smirnoff Date: Wed, 9 Oct 2013 12:00:38 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r256186 - head/sys/netinet X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Oct 2013 12:00:39 -0000 Author: glebius Date: Wed Oct 9 12:00:38 2013 New Revision: 256186 URL: http://svnweb.freebsd.org/changeset/base/256186 Log: When processing ACK in tcp_do_segment, use sbcut_locked() instead of sbdrop_locked() to cut acked mbufs from the socket buffer. Free this chain a batch manner after the socket buffer lock is dropped. This measurably reduces contention on socket buffer. Sponsored by: Netflix Sponsored by: Nginx, Inc. Approved by: re (marius) Modified: head/sys/netinet/tcp_input.c Modified: head/sys/netinet/tcp_input.c ============================================================================== --- head/sys/netinet/tcp_input.c Wed Oct 9 11:57:53 2013 (r256185) +++ head/sys/netinet/tcp_input.c Wed Oct 9 12:00:38 2013 (r256186) @@ -1461,6 +1461,7 @@ tcp_do_segment(struct mbuf *m, struct tc u_long tiwin; char *s; struct in_conninfo *inc; + struct mbuf *mfree; struct tcpopt to; #ifdef TCPDEBUG @@ -2718,15 +2719,17 @@ process_ACK: SOCKBUF_LOCK(&so->so_snd); if (acked > so->so_snd.sb_cc) { tp->snd_wnd -= so->so_snd.sb_cc; - sbdrop_locked(&so->so_snd, (int)so->so_snd.sb_cc); + mfree = sbcut_locked(&so->so_snd, + (int)so->so_snd.sb_cc); ourfinisacked = 1; } else { - sbdrop_locked(&so->so_snd, acked); + mfree = sbcut_locked(&so->so_snd, acked); tp->snd_wnd -= acked; ourfinisacked = 0; } /* NB: sowwakeup_locked() does an implicit unlock. */ sowwakeup_locked(so); + m_freem(mfree); /* Detect una wraparound. */ if (!IN_RECOVERY(tp->t_flags) && SEQ_GT(tp->snd_una, tp->snd_recover) &&