Received: from SOUTH-STATION-ANNEX.MIT.EDU by po7.MIT.EDU (5.61/4.7) id AA03315; Sun, 10 Dec 95 23:24:43 EST Received: from LOLA-GRANOLA.MIT.EDU by MIT.EDU with SMTP id AA27415; Sun, 10 Dec 95 23:24:48 EST Received: (from ghudson@localhost) by lola-granola.MIT.EDU (8.6.11/8.6.11) id XAA05820; Sun, 10 Dec 1995 23:24:49 -0500 Message-Id: <199512110424.XAA05820@lola-granola.MIT.EDU> To: proven@MIT.EDU Subject: Chris G Demetriou: John Birrell: Re: pthreads (?) on NetBSD/Alpha? Date: Sun, 10 Dec 1995 23:24:48 EST From: Greg Hudson I've sent a reply to this; I'll forward it to you when I get it. ------- Forwarded Message Replied: Sun, 10 Dec 1995 23:19:08 EST Replied: "Chris G Demetriou netbsd-developers@netbsd.org, cgd@BALVENIE.PDL.CS.CMU.EDU" Received: from SOUTH-STATION-ANNEX.MIT.EDU by po6.MIT.EDU (5.61/4.7) id AA26062; Sun, 10 Dec 95 22:53:58 EST Received: from pain.lcs.mit.edu by MIT.EDU with SMTP id AA24951; Sun, 10 Dec 95 22:53:22 EST Received: (from daemon@localhost) by pain.lcs.mit.edu (8.6.12/8.6.9) id WAA12034; Sun, 10 Dec 1995 22:29:11 -0500 Received: from BALVENIE.PDL.CS.CMU.EDU by pain.lcs.mit.edu (8.6.12/8.6.9) with SMTP id WAA12007 for ; Sun, 10 Dec 1995 22:28:44 -0500 Received: from localhost by BALVENIE.PDL.CS.CMU.EDU id aa14378; 10 Dec 95 22:28 EST To: netbsd-developers@netbsd.org Cc: cgd@BALVENIE.PDL.CS.CMU.EDU X-Copyright: Copyright 1995, Christopher G. Demetriou. All rights reserved. X-Notice: Duplication and redistribution prohibited without consent of the author. Subject: John Birrell: Re: pthreads (?) on NetBSD/Alpha? Date: Sun, 10 Dec 1995 22:28:22 -0500 Message-Id: <561.818652502@BALVENIE.PDL.CS.CMU.EDU> From: Chris G Demetriou Sender: owner-netbsd-developers@NetBSD.ORG Precedence: first-class X-Loop: netbsd-developers@NetBSD.ORG John Birrell, one of the earliest users of NetBSD/Alpha mentioned that he got thread support working on the alpha a few days ago. I asked for diffs, etc., assuming that it was based on Chris Provenzano's pthreads library... "Wrong." I got the following back, and am forwarding it with permission. Any comments? I've thought for a while that, as long as it doesn't cost much, making thread-safe versions of various libraries the _default_ is a good idea... chris - ------- Forwarded Message Replied: Sun, 10 Dec 1995 19:04:43 -0500 Replied: "John Birrell " Received: from BALVENIE.PDL.CS.CMU.EDU by NIAGARA.NECTAR.CS.CMU.EDU id aa12769; 9 Dec 95 19:30:15 EST Received: from werple.mira.net.au by BALVENIE.PDL.CS.CMU.EDU id aa14423; 9 Dec 95 19:29 EST Received: from cimaxp1.UUCP (Ucimlogi@localhost) by werple.net.au (8.7/8.7.1) with UUCP id KAA14329 for Chris_G_Demetriou@BALVENIE.PDL.CS.CMU.EDU; Sun, 10 Dec 1995 10:42:11 +1100 (EST) Message-Id: <199512092342.KAA14329@werple.net.au> X-Authentication-Warning: werple.net.au: Ucimlogi set sender to cimaxp1!jb using -f Received: by cimaxp1.cimlogic.com.au; (5.65/1.1.8.2/10Sep95-0953AM) id AA00618; Sun, 10 Dec 1995 10:42:17 +1100 From: John Birrell Subject: Re: pthreads (?) on NetBSD/Alpha? To: Chris G Demetriou Date: Sun, 10 Dec 1995 10:42:17 +1100 (EST) Cc: jb@cimlogic.com.au In-Reply-To: <1029.818544916@BALVENIE.PDL.CS.CMU.EDU> from "Chris G Demetriou" at Dec 9, 95 04:35:16 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Chris, There's a bit a story to this. Having had a good look at libpthread in NetBSD (i386 only), I concluded that it should be trashed. It doesn't contain sufficient functionality to get a serious threaded application to work. > > so, was it pthreads that you ported to NetBSD/Alpha? if so, could you I started with Chris Provenzano's MIT pthreads using NetBSD/i386-current. His test programs built and ran and therefore supposedly proved that the pthreads library worked. I built our threaded applications (working on OSF/1, VxWorks and LynxOS) against the pthread library and couldn't get our test harnesses to run at all. So I started debugging the pthread library. As it turned out, there were a lot of bugs, some the result of the basic design. Provenzano tried to implement user-space file descriptors that don't match those that the kernel knows about. He builds the pthread library from his own libc code that was NetBSD version 0.9. Instead of having the syscalls return their normal values, he has them return "minus errno". His scheduling code is spread throughout the libc functions that are duplicated in libpthread. And the list goes on.... We (CIMlogic) reviewed the pthread design and our ability to support code based on it and NetBSD. The outcome of that review was the decision to create and support a local version of NetBSD's libc that could be built non-threaded and threaded from the same source. [You might remember that I have mentioned this a few times in mail] We modified NetBSD libc source and added our own scheduler. Before NetBSD announced the release of 1.1, we faced the issue of what OS we would ship customers on the i386 platform. We decided to go with FreeBSD instead of NetBSD simply because there was a formal release available on CD (no flames, please 8-). The subject of pthreads came up on the FreeBSD-hackers mailing list about the same time as our decisions were being made. I commented about the problems with pthreads. This lead to the decision by the FreeBSD core to add thread support to FreeBSD's libc in a way that would... (a) have no effect on existing programs (meaning that it had to be possible to build the normal libc); (b) allow a threaded version of libc (libc_r.a) to be built that would have a user-thread implementation; (c) the user-thread implementation had to allow a pthread library to be built. The directory structure we're using is.. /usr/src/lib/libc - Normal libc stuff with edits to do #ifdef _THREAD_SAFE where required. /usr/src/lib/libc_r - Makefiles reference source in libc where the same source is used; thread specific source is in the libc_r tree. /usr/src/lib/libc_r/uthread - Contains our user-thread implementation which can be used _instead_ of Provenzano's pthread user-thread implementation. /usr/src/lib/libc_r/pthread - Provenzano's user-thread implementation will go here (eventually, although it is staying a FreeBSD port [in their language] for the time being). Now we're committed to _both_ NetBSD (for Alpha) and FreeBSD (since they can give us a system that comes with threads and a lot of working applications). We'll be maintaining only a few pieces of FreeBSD source locally. For NetBSD there is much more code for us to support locally because I have not (yet) convinced J.T. to modify NetBSD's libc in the same way that FreeBSD is being modified. I was sort of hoping the Provenzano would have some success since he comes from MIT and has contributed to *BSD for some time. He is keen to get a threaded libc that can be used with X thread support. > please: > (1) send the diffs back to the author (i'd like to make > pthreads support NetBSD/Alpha out of the box), Chris Provenzano says he has been talking to mycroft about integrating pthreads into NetBSD's libc. I haven't heard whether anything is to come of this. I'm still trying to persuade J.T. to change NetBSD's errno implementation to call __error so that all libraries built with NetBSD can be linked into a threaded program. We won't be working with pthreads anymore. > (2) send me the diffs (from the latest version), and Don't have 'em. Can't (won't) do 'em. 8-). > (3) point me to the latest pthreads release (I forget where > it is... 8-) Chris Provenzano's home page is... http://www.mit.edu:8001/people/proven/pthread.html The ftp site is (I think)... sipb.mit.edu:/pub/pthreads Provenzano's home page references this. > > I'd like to play around with them a bit.... In the short term, I'm not sure there is much I can do to help. It takes quite a while to get the build of /usr/src/lib/libc_r right and I'm currently only working on doing this for FreeBSD. Of course, if you can influence NetBSD core to modify libc for thread support, then everyone can 'play around with them a bit'. 8-). Trevor Blackwell expressed an interest too. > > thanks. > > > later, > > chris > Regards, - - -- John Birrell CIMlogic Pty Ltd jb@cimlogic.com.au 119 Cecil Street Ph +61 3 9690 9600 South Melbourne Vic 3205 Fax +61 3 9690 6650 Australia Mob +61 18 353 137 - ------- End of Forwarded Message ------- End of Forwarded Message