From owner-svn-src-all@freebsd.org Wed May 18 03:55:55 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7FEB0B3F98E; Wed, 18 May 2016 03:55:55 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4B05B1448; Wed, 18 May 2016 03:55:55 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u4I3tsqS012822; Wed, 18 May 2016 03:55:54 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u4I3tskK012821; Wed, 18 May 2016 03:55:54 GMT (envelope-from markj@FreeBSD.org) Message-Id: <201605180355.u4I3tskK012821@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Wed, 18 May 2016 03:55:54 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r300110 - head/sys/kern 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: 2.1.22 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, 18 May 2016 03:55:55 -0000 Author: markj Date: Wed May 18 03:55:54 2016 New Revision: 300110 URL: https://svnweb.freebsd.org/changeset/base/300110 Log: Do not acquire the thread lock in hardclock_cnt() unless needed. This function only sets thread flags if a SIGPROF or SIGVTALRM timer has fired, which is almost never the case. MFC after: 2 weeks Modified: head/sys/kern/kern_clock.c Modified: head/sys/kern/kern_clock.c ============================================================================== --- head/sys/kern/kern_clock.c Wed May 18 03:50:21 2016 (r300109) +++ head/sys/kern/kern_clock.c Wed May 18 03:55:54 2016 (r300110) @@ -570,9 +570,11 @@ hardclock_cnt(int cnt, int usermode) flags |= TDF_PROFPEND | TDF_ASTPENDING; PROC_ITIMUNLOCK(p); } - thread_lock(td); - td->td_flags |= flags; - thread_unlock(td); + if (flags != 0) { + thread_lock(td); + td->td_flags |= flags; + thread_unlock(td); + } #ifdef HWPMC_HOOKS if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))