From owner-freebsd-java@freebsd.org Thu Nov 12 16:26:09 2015 Return-Path: Delivered-To: freebsd-java@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 16C0DA2DBB0 for ; Thu, 12 Nov 2015 16:26:09 +0000 (UTC) (envelope-from achill@matrix.gatewaynet.com) Received: from smadev.internal.net (host3.dynacom.ondsl.gr [62.103.35.211]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 456B3186B for ; Thu, 12 Nov 2015 16:26:07 +0000 (UTC) (envelope-from achill@matrix.gatewaynet.com) Received: from smadev.internal.net (smadev [10.9.200.131]) by smadev.internal.net (8.14.7/8.14.7) with ESMTP id tACGPwxF049788 for ; Thu, 12 Nov 2015 18:25:58 +0200 (EET) (envelope-from achill@matrix.gatewaynet.com) Message-ID: <5644BD96.9000005@matrix.gatewaynet.com> Date: Thu, 12 Nov 2015 18:25:58 +0200 From: Achilleas Mantzios User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: freebsd-java@freebsd.org Subject: Re: Thread.sleep is very incorrect on kern.hz FreeBSD-10 + openjdk8. References: <5644BB9A.4060807@smartspb.net> In-Reply-To: <5644BB9A.4060807@smartspb.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: freebsd-java@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Porting Java to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Nov 2015 16:26:09 -0000 On 12/11/2015 18:17, Sergey Potapov wrote: > Hello! > > FreeBSD-10.1 without tunning. > openjdk8 without tunning (pkg install). > > > Thread.sleep depends on kern.hz sysctl variable. > > Simple program and more detailed version information attched. > openjdk7 tested with kern.hz=2000 -- same results. > > kern.hz: 100 > > 1000 times Thread.sleep(1) 19994 milliseconds > 1000 times Thread.sleep(2) 19997 milliseconds > 1000 times TimeUnit.MICROSECONDS.sleep(100) 20000 milliseconds > > kern.hz: 1000 > > 1000 times Thread.sleep(1) 2002 milliseconds > 1000 times Thread.sleep(2) 3000 milliseconds > 1000 times TimeUnit.MICROSECONDS.sleep(100) 2001 milliseconds > > > kern.hz: 2000 > > 1000 times Thread.sleep(1) 1500 milliseconds > 1000 times Thread.sleep(2) 2500 milliseconds > 1000 times TimeUnit.MICROSECONDS.sleep(100) 1500 milliseconds > How about using even larger values for kern.hz ? > Linux and Windows are much better (but don't support anything less 1ms too). > > Linux: > > sysctl: cannot stat /proc/sys/kern/hz: No such file or directory. > > 1000 times Thread.sleep(1) 1077 milliseconds > 1000 times Thread.sleep(2) 2078 milliseconds > 1000 times TimeUnit.MICROSECONDS.sleep(100) 1079 milliseconds > > Windows (with sysctl command removed): > > 1000 times Thread.sleep(1) 1002 milliseconds > 1000 times Thread.sleep(2) 2000 milliseconds > 1000 times TimeUnit.MICROSECONDS.sleep(100) 1002 milliseconds > > -- > Sergey Potapov. > > > > > _______________________________________________ > freebsd-java@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-java > To unsubscribe, send any mail to "freebsd-java-unsubscribe@freebsd.org" -- Achilleas Mantzios IT DEV Lead IT DEPT Dynacom Tankers Mgmt