X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:message-id:from:reply-to:to:subject :references:in-reply-to:content-type; q=dns; s=default; b=nD2PXh XJKXyIYEaqlRGmQu+B+W1ZfrHiWaZj7ILekEImVCag38NkzI65begS46X2ZgJZ+8 iqp4tqgwjRq0u/oYv2ubF/+5ryjMmRv9oSymCkoQWJ18xUJGtrb327akEXXgA3pL I2dBjnEK4ULEni5VHDZStFgNLYSPQnLXECYHM= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:message-id:from:reply-to:to:subject :references:in-reply-to:content-type; s=default; bh=GWXsz6Epmeav EP/FlNelNYOBcvo=; b=E6g1JkL4zvjBJhIvc7BpstEjXYOcza+1TGH3nE/qwALr xYLm0WprSHK5F2hxv79G7QBJXJ1dFdduZVcYNXbqyhHKni4t8KE+AYPedSTfObTo Q8yhB664I4UzWXRnGsQqap2i1/ZyE3bE5OEI8J9qEB2EkQ+KN6E5K1DgjzOcTvg= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,NORMAL_HTTP_TO_IP,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=seven, Seven, 11000, UD:X X-HELO: lb3-smtp-cloud7.xs4all.net Date: Mon, 26 Nov 2018 19:07:44 +0100 Message-ID: <093958e15892f03eecfe6eea1ce6566f@smtp-cloud7.xs4all.net> From: Houder Reply-To: cygwin AT cygwin DOT com To: cygwin AT cygwin DOT com Subject: Re: No thread safety in clock_gettime (hires_ns::prime) References: <20181126170140 DOT GO30649 AT calimero DOT vinschen DOT de> In-Reply-to: <20181126170140.GO30649@calimero.vinschen.de> Content-Type: text/plain; charset=UTF-8; format=fixed User-Agent: mua.awk 0.99 On Mon, 26 Nov 2018 18:01:40, Corinna Vinschen wrote: > > On Nov 23 11:27, James E. King III wrote: [snip] > > I found that a call to > > clock_gettime(CLOCK_MONOTONIC, ..) has a one-time initialization that > > is not thread-safe. If two threads call this at the same time, they > > will race. The results I am seeing are typically that one of the two > > callers get a timespec structure with zero values, and no error return > > code from the call. > > Thanks for the testcase, but I can't reproduce the problem, neither on > 32 bit nor on 64 bit. I tweaked your makefile to have a 100K loop I > started multiple times with differently optimzed code, but to no avail. > > To account for that, I inspected the code doing the initialization and > found that it uses REALTIME priority when trying to make sure multiple > threads don't collide. This is a bit on the dangerous side, apparently. > > I tweaked the code to use a spinlock instead. > > I'm just about to upload new developer snapshots to > https://cygwin.com/snapshots/ > > Should be up in 10 mins or so. Can you please try if this fixes the > problem for you? - only replaced the cygwin1.dll ... Henri 64-@@ uname -a CYGWIN_NT-6.1 Seven 2.11.3(0.329/5/3) x86_64 Cygwin 64-@@ ls -l /bin/cygwin1* -rwxr-xr-x 1 Henri None 3339661 Nov 8 14:36 /bin/cygwin1-2.11.2.X -rwxr-xr-x 1 Henri None 3337995 Nov 26 18:43 /bin/cygwin1-64-20181126.X -rwxr-xr-x 1 Henri None 3337995 Nov 26 18:43 /bin/cygwin1.dll 64-@@ cd threads 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ make test 64-@@ vi Makefile 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ #... wait a while ... 64-@@ for loop in {1..100}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..1000}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..1000}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..1000}; do ./cyg_hires_clock_race.exe; done 64-@@ for loop in {1..10000}; do ./cyg_hires_clock_race.exe; done 64-@@# That is enough! ===== -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple