From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 51F2367A00 for ; Wed, 29 Mar 2006 14:12:04 +1100 (EST) Subject: Re: [OT] ppc64 serialization problem From: Benjamin Herrenschmidt To: Greg Smith In-Reply-To: <1143597506.3075.53.camel@localhost.localdomain> References: <1143597506.3075.53.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 29 Mar 2006 14:11:42 +1100 Message-Id: <1143601903.3585.2.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2006-03-28 at 20:58 -0500, Greg Smith wrote: > We have a multi-threaded app running on a p520 in 64 bit mode. > > Thread A does > > pthread_mutex_lock(&lock); > u32 &= ~bitA; > pthread_mutex_unlock(&lock); > > and Thread B does > > pthread_mutex_lock(&lock); > u32 |= bitB; > A = u32; > B = u32; > pthread_mutex_unlock(&lock); > > On rare occasions, values A and B will differ! In the examples that I > have seen, there is contention with `lock'. This phenomenon does not > occur on ppc32 or a number of other architectures that we support. How did you actually "look" at A and B ? is that also protected by the lock ? > I confess I do not know the linux version nor the glibc version nor what > pthreads implementation is being used. I'll find that out shortly. That's fairly important to know those yes. > What I am curious about is where the problem might lie > (kernel/lib/pthreads/app) so I can ask the right people. > > Thank you for your patience, > Greg Smith > > > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-dev