From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/9122 Path: news.gmane.org!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: atomic.h cleanup Date: Fri, 15 Jan 2016 01:46:38 +0100 Message-ID: <20160115004638.GI13558@port70.net> References: <20160110165718.GR238@brightrain.aerifal.cx> <20160110173509.GG2016@debian> <20160111163544.GI2016@debian> <1452532349.28095.10.camel@inria.fr> <20160111190356.GA13558@port70.net> <1452545810.28095.12.camel@inria.fr> <20160114221257.GS238@brightrain.aerifal.cx> <1452811068.5797.9.camel@inria.fr> <20160114233223.GA238@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1452818828 31964 80.91.229.3 (15 Jan 2016 00:47:08 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 15 Jan 2016 00:47:08 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-9135-gllmg-musl=m.gmane.org@lists.openwall.com Fri Jan 15 01:46:52 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1aJsXU-0006UM-Fa for gllmg-musl@m.gmane.org; Fri, 15 Jan 2016 01:46:52 +0100 Original-Received: (qmail 3176 invoked by uid 550); 15 Jan 2016 00:46:50 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 3158 invoked from network); 15 Jan 2016 00:46:50 -0000 Mail-Followup-To: musl@lists.openwall.com Content-Disposition: inline In-Reply-To: <20160114233223.GA238@brightrain.aerifal.cx> User-Agent: Mutt/1.5.24 (2015-08-30) Xref: news.gmane.org gmane.linux.lib.musl.general:9122 Archived-At: * Rich Felker [2016-01-14 18:32:24 -0500]: > On Thu, Jan 14, 2016 at 11:37:48PM +0100, Jens Gustedt wrote: > > Am Donnerstag, den 14.01.2016, 17:12 -0500 schrieb Rich Felker: > > > There are already multiple reasons we don't use the compiler's > > > atomics, either directly or indirectly via stdatomic.h. They're not > > > supported in some old/alternative compilers, they generate highly > > > suboptimal code even on modern compilers for some important archs > > > (e.g. ARM), > > > > I have seen some pretty good assembler when using the > > __atomic... builtins, so I can't completely follow, here. > > It generates "dmb sy" all over the place instead of "dmb ish". > Synchronizing with external bus devices is NOT something you want to > happen in thread synchronization primitives. > fixed in gcc-6 :) https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=224317 (not backported to earlier branches though)