From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/5606 Path: news.gmane.org!not-for-mail From: Jens Gustedt Newsgroups: gmane.linux.lib.musl.general Subject: Re: C11 threads Date: Sat, 26 Jul 2014 01:26:09 +0200 Message-ID: <1406330769.6438.85.camel@eris.loria.fr> References: <1406282437.6438.34.camel@eris.loria.fr> <20140725104056.GO9928@port70.net> <1406286404.6438.38.camel@eris.loria.fr> <20140725154141.GC4038@brightrain.aerifal.cx> <1406308202.6438.63.camel@eris.loria.fr> <20140725221950.GE4038@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-cR+R9oycJJTPXvD8WT1b" X-Trace: ger.gmane.org 1406330799 4921 80.91.229.3 (25 Jul 2014 23:26:39 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 25 Jul 2014 23:26:39 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-5611-gllmg-musl=m.gmane.org@lists.openwall.com Sat Jul 26 01:26:35 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1XAosi-0001Tk-E8 for gllmg-musl@plane.gmane.org; Sat, 26 Jul 2014 01:26:32 +0200 Original-Received: (qmail 31910 invoked by uid 550); 25 Jul 2014 23:26:23 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 31885 invoked from network); 25 Jul 2014 23:26:23 -0000 X-IronPort-AV: E=Sophos;i="5.01,733,1400018400"; d="scan'";a="87047332" In-Reply-To: <20140725221950.GE4038@brightrain.aerifal.cx> Face: 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 u+rU6wJnprxQf/JvP7beffH5fBIwGIZqEutJUlCKSNoFjYbQiihOkFmih0FJgSUGIpGxstE6RwiLQmsyzcXZesO8N1773YOHKPfUv/uxP726ePjsVNVoT9WZjMq02kRpEKay9+UPXjQmAL1991UuDZ+fGQulSVQrpuqg4pWkkupSjVGshtGZJpzQ9DysfQqZIkgzR7 jAc+qAFrm2xTIRJJKnr0okTfCnQKLRlo9MUicGWL7dcnCnytoOTKTxpERpBv8moomm7AZFjEddb9EiHdhJhPJdYanQKUZrivmH7Pnlm+itFuVgdi7WkpSSJdFlqRwRugLAkQakXJQ06cAhcB0tnRI0mstOllKYEvk8qJJGj8IygID16hwZBGIzIsIXCRREq6DGSsu9RkBYBBldKbCFwbMnA2mH8wKIrbQrGY1WkKbQ6DFkWOQEicMks8JTEQRJI0LOLJbvxwosTMlMk0kYbjTCGci4gzrr0Sod0YQFHWiSuRTHMkbRaCCxMZlh2FLGQLEjBmHFIhUBrEI0OlgYnyNN0LFKliYxGeT69rouqtOjP5+lLEtxugosgOjNHj7ZRGmwjaDoGX9skKEQQIFptkAIjIWckCQIrE9ija8aOznk5wiwh9lw8aeMlMamUeEKis4wOFiaFRtpEYxBJSoQA4ZM4ksgSPG4E9Siibjt02xUaUQsnzFFfSZlPM4TRlPp7yQWCs/PzlMs53HrMRLGPt/f2UFYRbkOzbGm6JkPgYjAgbVo6I/Ntup0unuPgWAK0RaLVy//AfVe864lgcWkicz1yloNvoJMmpFLTsiCJNIFt0VERHdcnGyxPW5598BmlJo6tVPc9v1RB2CHdqMWOYpkLCwHnhyHVTHNcpTxUrVCp1rAtyYZ1w0i3SLFk89A3/g2UZH3O4ubL30RxsU5ldhkpDFJIbGFRE4rYSLQQRHGEJQQeFm7gYHaev98CuO6NF62q1hqTKktJlKarNW0JDZUgHA9dys/Y q4emnQ3Df3nxj7z7+t2f+pO/Ysv5U0dm525uKYty3wCetPjRdYNcjaaQabq1Oq1MkVOKkc1reGFhiWIuj7C6JGlKyZNsNor3n7eFStLlkcoKz61fvX/79u3T9cWliTBWvrQEHa0QQmIZgdIK27FQmaKVxIRbN+77z5/4sT/+1PjJEycmosWVmXJvP3YpZM3aNYyuWz 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 xWxyQg9l57BATZZDpuCgH5PMrVxM3G3g513WfNDW3liYRGsPN1ua2LHtq0zM6dOPfmqCDx15227/+ILd58EaNa717/00smp3bsvo7fcS3VpGTcAKV2q1QZJ3MVIC88JsFJN2c+xbrDM+aHPlqE+ji0vY7kWvaFhaaXJzs3nYaoNNq/tJ1/tsiwtnpEOtz/+HHNLMXG 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 1LklihlU2u6NBtNZDaohXHIDKadYWRLsZkZFhgNCaLcB2XzECWalAZhR6v9vzx472v+BF/dxSu3FPf9cY3z0TNLgO+YFNfHzozJHFE4CvW1CPGBvtYabQ5YQuON+aI7YCqUTSX2hgTUeop025IstSiv1wiUQu4fkiz2SBTHaSQ9AQOaZqBk6MTdzFGYAnB0FAvWjD9 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 kELLRU3y0d5Cg1aEZBqSxQJdtprXL5546guXm6QtCwmKOTrvC2NoSq8tw8fYSDx9t8tATVSqNOo16lzdech7Ndrz/a4e/9fqr05+57dCTW7edtz/fE2JIySyHlxqKr8+3OFXooykND8ocf1vwuD1WHO1G5AKPUi5EYVGpLeA4OcqhZtVASKtjkLZFpjM6nZjNG0dnN 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 C3d0WolfKhTp6clRyhcg04xtGCHt1Dh/rExRamYWGyxXa7xn1yYuvkAwP7fClg0Zhx+qr/rM7d+Yesc73nHD5OW7Zh478tRzPxACH/iRa245duzkAdsJfMuy8aXm/FUFlpeWWOm2WZidI9WapaUlFIaTlQ4jfR6/vO9D2NE32LTeYnZOUmnA6PAohx9+qnTy1NnrP/ Cj15cu23XZI4/826Px/xqB37z547sPH374oOvnKTsOb+1zuCoImZARM8ZiLlKkXcWOcoFRJ+Do/CwFO4e2DEe+9Ti+ZXA8ny/cU+X4bMKRZxZIVEiqXI6/+NKuUzPHb7z40ovnX3zx+Ctuq38HyuqWG7Tu+A0AAAAASUVORK5CYII= X-Mailer: Evolution 3.4.4-3 Xref: news.gmane.org gmane.linux.lib.musl.general:5606 Archived-At: --=-cR+R9oycJJTPXvD8WT1b Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Am Freitag, den 25.07.2014, 18:19 -0400 schrieb Rich Felker: > Since glibc is going that way, I think we should keep the type sizes > the same but leave it explicitly undefined to mix calls to C11 and > POSIX functions on the same synchronization objects. yes, defitively. Not even for the synchronization functions, basically none from pthread and C11 thread should be mixed, I think. I thought of figuring out a way to make this even a link error. > Could you elaborate? Perhaps we're thinking of different things. probably. The C11 specification is so bad, that some of the functions don't even have a semantic description of what they are supposed to achieve. E.g tss_t completely lacks a description of what a destructor is, what the "iterations" in TSS_DTOR_ITERATIONS describe etc. Parts of it are or will be adressed TC, but there is much more. I wrote my findings up here http://gustedt.wordpress.com/2012/10/14/c11-defects-c-threads-are-not-reali= zable-with-posix-threads/ > One aspect is that all POSIX synchronization functions are full > barriers, whereas presumably the C11 ones are proper acquire/release > barriers as appropriate for the operation being performed. That is probably the intention. But e.g mtx_lock is only required to synchronize with calls to mtx_unlock, not with other calls to mtx_lock or similar. The term "lock" isn't even defined. > Another is Austin Group issue #755, which I'm hoping the WG14 will not > rule the same way on. The Austin Group's resolution for POSIX mutexes > makes recursive and error-checking mutexes very expensive and requires > threads to maintain a record of all such mutexes they own. I have not > yet implemented this in musl but I plan to do so soon (BTW this needs > to be added to the roadmap). I am not sure that I completely understand what this is about. But in any case, C threads don't have error checking :) > > The advantages that I see that this doesn't need all that attr stuff > > and has no concept of cancellation. >=20 > Cancellation is rather irrelevant to the synchronization primitives. > Obviously C11's lack of cancellation makes C11 threads much easier to > implement if you're not also doing POSIX threads, but if you're doing > both, the fact that C11 lacks a cancellation function makes almost no > difference (just one simple cleanup function in condvar wait). There is a bit more, maybe. __timedwait does cleanup push and pop and messes around with cancelbuf. (But probably I just don't understand enough what's going on, here.) In any case, without attributes and possible cancelation, thrd_create becomes significantly shorter than pthread_create. And to my limited experience having well defined atomics that are integrated in the language, often helps to completely avoid mutexes and conditions. > > > and definitely allows smaller size if the application > > > only uses them (but of course makes libc.a and libc.so larger). > >=20 > > If we use weak aliases, this basically blows up the symbol table a > > bit. > >=20 > > When I strip my test executable, it is impressively small. >=20 > Yes, this is one reason I don't want __-prefixed symbols for > everything, just functions that really _need_ namespace-safe versions. > We should probably do some linking tests against all the C11 functions > to make sure they're not pulling in functions outside the C11 > namespace and add __-prefixed versions of those functions only, rather > than preemptively trying to guess what needs protection. I tried to do that already. > > > > For the types this should be easy to have them typedef'ed to some > > > > opaque struct. > > >=20 > > > For the types that vary per-arch, I don't see any way around having > > > them in the alltypes.h.in bits. > >=20 > > The only types that seem to be in bits are mutex and condition. All > > others seem to be arch independent. >=20 > Ah yes the others are probably not needed for C11. >=20 > > On the long we should probably have __pthread names in the alltypes.h > > files and typedef these in pthread.h and threads.h respectively. >=20 > That doesn't work because both sys/types.h and pthread.h have to > expose the pthread names. >=20 > > > As for the constants, which ones are > > > you talking about? > >=20 > > the mtx_ constants are the critical ones. > >=20 > > thrd_error and friends can easily be mapped to EXXX error codes from > > errno.h. Since these names are all reserved anyway, including errno.h > > shouldn't do much harm. >=20 > I don't think including errno.h implicitly is permitted. E* is only > reserved when errno.h is included. Anyway this is somewhere we wasnt > to agree with glibc on the values; I suspect they'll just use values > 1,2,... rather than errno codes. If so, that means we really need a > wrapper function rather than just an alias. Hm, not sure that I follow. I only need EBUSY, EINVAL, ENOMEM, and ETIMEDOUT, and effectively only that these are consistent with the rest of the C library, which for this implementation of C threads will always be musl. > > > I don't think it's so easy to directly use the > > > POSIX ones for C11 since they have some different semantics (flag bit= s > > > vs enumeration-style) for a few. > >=20 > > the mtx_ ones are basically flags, just as the PTHREAD_MUTEX_ ones. > > This fits well with the actual values of these in musl. >=20 > The PTHREAD_MUTEX_* ones are not flags; each corresponds to a single > type and they are not combinable. ah, ok, anyhow the only one that I am really interested in is PTHREAD_MUTEX_RECURSIVE. So perhaps I can push that down to the implementation. > The C11 ones are combinable, but mtx_timed is useless yes, I think I already noted that in the file that I attached to my initial mail > -- there's no need to care whether it will be > used for timed operations when it's initialized. >=20 > BTW n1570 only has 4 possible values to pass to mtx_init, but reads > (7.26.4.2 p2): >=20 > "The mtx_init function creates a mutex object with properties > indicated by type, which must have one of the six values:" >=20 > Any idea if six is just a mistake or if there are some values missing > from the list? It is just a leftover, and has/willbe been corrected. To summarize, I'd need to get EBUSY, EINVAL, ENOMEM, ETIMEDOUT and TSS_DTOR_ITERATIONS from somewhere. Jens --=20 :: INRIA Nancy Grand Est ::: AlGorille ::: ICube/ICPS ::: :: ::::::::::::::: office Strasbourg : +33 368854536 :: :: :::::::::::::::::::::: gsm France : +33 651400183 :: :: ::::::::::::::: gsm international : +49 15737185122 :: :: http://icube-icps.unistra.fr/index.php/Jens_Gustedt :: --=-cR+R9oycJJTPXvD8WT1b Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEABECAAYFAlPS55EACgkQD9PoadrVN+KCuQCfYLpGYyKnqtG4EUlX06FoTU3B TRoAmgI/ENdsG3TZ3jxNndrliUt9gP6s =UJYo -----END PGP SIGNATURE----- --=-cR+R9oycJJTPXvD8WT1b--