From owner-svn-src-stable@FreeBSD.ORG Fri Mar 12 00:51:25 2010 Return-Path: Delivered-To: svn-src-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E910A106566B; Fri, 12 Mar 2010 00:51:25 +0000 (UTC) (envelope-from delphij@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id BC0ED8FC23; Fri, 12 Mar 2010 00:51:25 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o2C0pPjj040811; Fri, 12 Mar 2010 00:51:25 GMT (envelope-from delphij@svn.freebsd.org) Received: (from delphij@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o2C0pP1W040809; Fri, 12 Mar 2010 00:51:25 GMT (envelope-from delphij@svn.freebsd.org) Message-Id: <201003120051.o2C0pP1W040809@svn.freebsd.org> From: Xin LI Date: Fri, 12 Mar 2010 00:51:25 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org X-SVN-Group: stable-7 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r205057 - stable/7/games/grdc X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Mar 2010 00:51:26 -0000 Author: delphij Date: Fri Mar 12 00:51:25 2010 New Revision: 205057 URL: http://svn.freebsd.org/changeset/base/205057 Log: MFC r203760: Improve time precision for grdc(6): Traditionally, grdc would obtain time through time(3) which in turn gets only the second part of clock (CLOCK_SECOND), and sleep for 1 second after each screen refresh. This approach would have two problems. First, we are not guaranteed to be waken up at the beginning of a whole second, which will typically exhibit as a "lag" on second number. Second, because we sleep for whole second, and the refresh process would take some time, the error would accumulate from time to time, making the lag variable. Make grdc(6) to use time(3) to get time only at the beginning, and sample time in CLOCK_REALTIME_FAST granularity after refreshing, and use the nanosecond part to caculate how much time we want to sleep. PR: bin/120813 Modified: stable/7/games/grdc/grdc.c Directory Properties: stable/7/games/grdc/ (props changed) Modified: stable/7/games/grdc/grdc.c ============================================================================== --- stable/7/games/grdc/grdc.c Fri Mar 12 00:51:13 2010 (r205056) +++ stable/7/games/grdc/grdc.c Fri Mar 12 00:51:25 2010 (r205057) @@ -59,6 +59,7 @@ main(argc, argv) int argc; char **argv; { +struct timespec ts; long t, a; int i, j, s, k; int n; @@ -136,9 +137,9 @@ int t12; attrset(COLOR_PAIR(2)); } + time(&now); do { mask = 0; - time(&now); tm = localtime(&now); set(tm->tm_sec%10, 0); set(tm->tm_sec/10, 4); @@ -193,7 +194,19 @@ int t12; } movto(6, 0); refresh(); - sleep(1); + clock_gettime(CLOCK_REALTIME_FAST, &ts); + if (ts.tv_sec == now) { + if (ts.tv_nsec > 0) { + ts.tv_sec = 0; + ts.tv_nsec = 1000000000 - ts.tv_nsec; + } else { + ts.tv_sec = 1; + ts.tv_nsec = 0; + } + nanosleep(&ts, NULL); + now = ts.tv_sec + 1; + } else + now = ts.tv_sec; if (sigtermed) { standend(); clear();