From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <5492EBAC.10502@siemens.com> Date: Thu, 18 Dec 2014 15:58:52 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <549072DC.1030901@xenomai.org> <549090FA.7000901@xenomai.org> <5492989C.9070106@siemens.com> <20141218141248.GN2012@hermes.click-hack.org> In-Reply-To: <20141218141248.GN2012@hermes.click-hack.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] [xenomai-forge] timer-internal consume a lot of cpu List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix , Ronny Meeus Cc: xenomai@xenomai.org On 2014-12-18 15:12, Gilles Chanteperdrix wrote: > On Thu, Dec 18, 2014 at 01:28:42PM +0100, Ronny Meeus wrote: >> On Thu, Dec 18, 2014 at 10:04 AM, Jan Kiszka wrote: >>> On 2014-12-18 09:00, Ronny Meeus wrote: >>>>> >>>>> A release of the glibc that fixes this issue. I must admit that I did >>>>> not track this problem lately. Jan likely knows better here. >>>>> >>>> >>>> Jan, >>>> >>>> what version glibc solves the priority inversion issue on conditional variables? >>>> I already tried the glibc 2.18 but the issue is still there. >>> >>> The bug is still not fixed, and discussion stalled again, see >>> https://sourceware.org/bugzilla/show_bug.cgi?id=11588 >>> >>> Jan >>> >>> -- >>> Siemens AG, Corporate Technology, CT RTC ITP SES-DE >>> Corporate Competence Center Embedded Linux >> >> Philippe, Jan >> >> as long as this issue is not fixed in glibc, it is not OK to use >> conditional variables > > I believe xenomai cobalt does not suffer from the same issue, > condition variables should work fine with priority inheritance. Yes, this is a mercury-only issue. Cobalt is fine as its own implementation of posix mutexes and condvars is correct in this regard. > > Otherwise, have you tried some alternate libc, such as musl: > http://www.musl-libc.org/ > > The following blog: > http://ewontfix.com/ > > Seems to show that the musl maintainers try and report glibc bugs > and avoid them in their implementation. > > I have not tried xenomai with musl at all, so, maybe it does not > even compile. But maybe just compiling a testcase for the condvar > issue with that libc would help know if it has the same issue or > not. Well, like with many of those "light-weight" re-implementations, the are "small" issues with bits required for real-time: http://git.musl-libc.org/cgit/musl/tree/src/thread/pthread_mutexattr_setprotocol.c Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux