From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Zelphir Kaltstahl Newsgroups: gmane.lisp.guile.devel,gmane.lisp.guile.user Subject: Re: map-par slower than map Date: Wed, 12 Oct 2022 21:29:34 +0000 Message-ID: <5608809c-89a2-118c-5c05-c46ac3a0e21b@posteo.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29870"; mail-complaints-to="usenet@ciao.gmane.io" Cc: guile-user , guile-devel To: Damien Mattei Original-X-From: guile-devel-bounces+guile-devel=m.gmane-mx.org@gnu.org Wed Oct 12 23:30:00 2022 Return-path: Envelope-to: guile-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oijIe-0007bZ-1U for guile-devel@m.gmane-mx.org; Wed, 12 Oct 2022 23:30:00 +0200 Original-Received: from localhost ([::1]:46424 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oijIb-0007iU-IO for guile-devel@m.gmane-mx.org; Wed, 12 Oct 2022 17:29:57 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44988) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oijIN-0007ha-PO for guile-devel@gnu.org; Wed, 12 Oct 2022 17:29:43 -0400 Original-Received: from mout02.posteo.de ([185.67.36.66]:58923) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oijIL-00049h-AA for guile-devel@gnu.org; Wed, 12 Oct 2022 17:29:43 -0400 Original-Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 62E4A240101 for ; Wed, 12 Oct 2022 23:29:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1665610177; bh=cSYKo/9mSfu0TevgYfLZumJ/UULypaoWrZMSyF7hEzQ=; h=Date:Subject:To:Cc:From:From; b=HyV0aHd8dUIQbXVrZC40nJ93n0p3Mb7qmFMB0bSVHsz8L7VbvyVXwU74y6A4VBtMt 6gDOQRbpTShGxIljHOoNxXzUGFtsPInNuxsn+RUAqm617pLe9e1AGFtYE2pCK/xbGT RUaUJpjgkLl36YTrRYDtRgYqF9j7Xv/eO82a2X46OJQsjG8kylcZsLXO3IDtvFqKdu dIePfAYPIyA3NJMLtiMrPZDlbR6ownruscub5TYaRpfmqFflWKS0JIso7A87iNOJ+6 UlzcbXlPRpTJh/yim9+X7eCebTtEl+UUZs4Ryive5ujiHlL8jD04pyg4yQ4jIbwCW5 9ukzfAxvvZoDA== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4Mnm4v2dkDz6tnX; Wed, 12 Oct 2022 23:29:35 +0200 (CEST) Content-Language: en-US In-Reply-To: Received-SPF: pass client-ip=185.67.36.66; envelope-from=zelphirkaltstahl@posteo.de; helo=mout02.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-devel-bounces+guile-devel=m.gmane-mx.org@gnu.org Original-Sender: "guile-devel" Xref: news.gmane.io gmane.lisp.guile.devel:21413 gmane.lisp.guile.user:18628 Archived-At: Hi! On 10/12/22 22:27, Damien Mattei wrote: > https://github.com/damien-mattei/library-FunctProg/blob/master/guile/logiki%2B.scm#L1674 > > i commited the current version of code here with all files but it is > huge.... :-/ > > On Wed, Oct 12, 2022 at 10:20 PM Damien Mattei > wrote: > >> Mutex? i do not think code has situation where dead lock could happen, it >> is a code about minimalising logic expressions, it uses minterms , minterms >> set is a set of minterms :like this: >> >> example: >> ((1 1 0) (1 1 1)) will be unified : (1 1 x) >> because 0 and 1 are replaced by x >> the minterms-set could have thousands of pair (mathematic not lisp) >> minterms to unify >> if there is more than one x as result there is no need to continue so i >> escape with a continuation: >> >> minterms-set = >> { >> ((1 0 1 0) (1 1 1 0)) >> ((1 0 1 0) (1 1 0 1)) >> ((1 0 1 0) (1 0 1 1)) >> ((1 0 1 0) (0 1 1 1)) >> ((0 1 1 0) (1 1 1 0)) >> ((0 1 1 0) (1 1 0 1)) >> ((0 1 1 0) (1 0 1 1)) >> ((0 1 1 0) (0 1 1 1)) >> ((0 1 0 1) (1 1 1 0)) >> ((0 1 0 1) (1 1 0 1)) >> ((0 1 0 1) (1 0 1 1)) >> ((0 1 0 1) (0 1 1 1)) >> ((0 0 1 1) (1 1 1 0)) >> ((0 0 1 1) (1 1 0 1)) >> ((0 0 1 1) (1 0 1 1)) >> ((0 0 1 1) (0 1 1 1)) >> } >> >> replace { } by () to have the list, other example at another level : >> >> minterms-set = >> { >> ((0 x 1 1) (x 1 1 1)) >> ((0 x 1 1) (1 x 1 1)) >> ((0 x 1 1) (1 1 x 1)) >> ((0 x 1 1) (1 1 1 x)) >> ((x 0 1 1) (x 1 1 1)) >> ((x 0 1 1) (1 x 1 1)) >> ((x 0 1 1) (1 1 x 1)) >> ((x 0 1 1) (1 1 1 x)) >> ((0 1 x 1) (x 1 1 1)) >> ((0 1 x 1) (1 x 1 1)) >> ((0 1 x 1) (1 1 x 1)) >> ((0 1 x 1) (1 1 1 x)) >> ((x 1 0 1) (x 1 1 1)) >> ((x 1 0 1) (1 x 1 1)) >> ((x 1 0 1) (1 1 x 1)) >> ((x 1 0 1) (1 1 1 x)) >> ((0 1 1 x) (x 1 1 1)) >> ((0 1 1 x) (1 x 1 1)) >> ((0 1 1 x) (1 1 x 1)) >> ((0 1 1 x) (1 1 1 x)) >> ((x 1 1 0) (x 1 1 1)) >> ((x 1 1 0) (1 x 1 1)) >> ((x 1 1 0) (1 1 x 1)) >> ((x 1 1 0) (1 1 1 x)) >> ((1 0 1 x) (x 1 1 1)) >> ((1 0 1 x) (1 x 1 1)) >> ((1 0 1 x) (1 1 x 1)) >> ((1 0 1 x) (1 1 1 x)) >> ((1 x 1 0) (x 1 1 1)) >> ((1 x 1 0) (1 x 1 1)) >> ((1 x 1 0) (1 1 x 1)) >> ((1 x 1 0) (1 1 1 x)) >> } >> >> here we see some minterms are already unified >> >> it is not easy to read even by me because i wrote the code many years ago >> and is split in many files, but here it is: >> >> (par-map function-unify-minterms-list minterms-set) >> >> {function-unify-minterms-list <+ (λ (L) (apply >> function-unify-two-minterms-and-tag L))} >> >> (define (unify-two-minterms mt1 mt2) >> (function-map-with-escaping-by-kontinuation2 >> (macro-function-compare-2-bits-with-continuation) mt1 mt2)) >> >> ;; (function-map-with-escaping-by-kontinuation2 >> (macro-function-compare-2-bits-with-continuation) '(1 1 0 1 0 1 1 0) '(1 >> 1 0 1 1 1 1 1)) >> >> ;; list1 = (1 1 0 1 0 1 1 0) >> ;; more-lists = ((1 1 0 1 1 1 1 1)) >> ;; lists = ((1 1 0 1 0 1 1 0) (1 1 0 1 1 1 1 1)) >> ;; clozure = # >> >> ;; #f >> ;; >> ;; (function-map-with-escaping-by-kontinuation2 >> (macro-function-compare-2-bits-with-continuation) '(1 1 0 1 0 1 1 0) '(1 >> 1 0 1 1 1 1 0)) >> >> ;; list1 = (1 1 0 1 0 1 1 0) >> ;; more-lists = ((1 1 0 1 1 1 1 0)) >> ;; lists = ((1 1 0 1 0 1 1 0) (1 1 0 1 1 1 1 0)) >> ;; clozure = # >> >> ;; '(1 1 0 1 x 1 1 0) >> (define (function-map-with-escaping-by-kontinuation2 clozure list1 . >> more-lists) >> (call/cc (lambda (kontinuation) >> (let ((lists (cons list1 more-lists)) >> (funct-continu ;; this function have the kontinuation in his environment >> (lambda (arg1 . more-args) >> (let ((args (cons arg1 more-args))) >> (apply clozure kontinuation args))))) ;; a tester: (apply clozure (cons >> conti args)) >> >> ;; (newline) >> ;; (dv list1) >> ;; (dv more-lists) >> ;; (dv lists) >> ;; (dv clozure) >> ;; (newline) >> >> (apply map funct-continu lists))))) >> >> (define-syntax macro-function-compare-2-bits-with-continuation ;; >> continuation version of macro-compare-2-bits >> ;; i need a macro because of external function to the clozure >> (syntax-rules () >> ((_) (let ((cnt 0)) ;; counter >> (lambda (continuation b1 b2) (if (equal? b1 b2) >> b1 >> (begin >> (set! cnt (add1 cnt)) ;; we leave with continuation in case cpt > 1, we >> can have used a flag too instead of a counter >> (when (> cnt 1) (continuation #f)) ;; escaping with the continuation >> 'x))))))) ;; return x in case of (b1,b2) = (O,1) or (1,0) >> >> what could have caused mutex if in the latter definition above (let ((cnt >> 0)) ;; counter was defined at top level and shared by all threads!!! yes >> there could have be some mutex but this is not the case, i think even all >> function are pure so why is it more slow with // than without? >> Damien >> >> On Wed, Oct 12, 2022 at 8:45 PM Maxime Devos >> wrote: >> >>> On 12-10-2022 19:19, Damien Mattei wrote: >>>> Hello, >>>> all is in the title, i test on a approximately 30000 element list , i >>> got >>>> 9s with map and 3min 30s with par-map on exactly the same piece of >>> code!? >>> > [...] >>> > >>>> translated from Scheme+ to Scheme: >>>> (define unified-minterms-set-1 (map function-unify-minterms-list >>>> minterms-set)) ;;(par-map function-unify-minterms-list minterms-set)) >>> The definition of 'function-unify-minterms-list' and 'minterms-set' is >>> missing. Without a test case, we can only speculate what's going on. >>> (E.g., maybe it grabs a mutex). >>> >>> Greetings, >>> Maxime. I don't want to scare anyone, just maybe warn about parallel map. I once tried to use Guile's parallel map function for a decision tree implementation (https://notabug.org/ZelphirKaltstahl/guile-ml/src/cf666801fea91c9fa8fa290764ff6c60b7f3949d/decision-tree.scm), where each branch while learning the tree would call parallel map again for sub branches and so on. Somehow it made Guile crash (I don't have the error message any longer, but I did post about it on the mailing list back then.). I never figured out, what went wrong. All I had was pure function calls and math inside the thing that parallel map was supposed to run. Ultimately I simply tried other parallelism constructs and when I switched to using futures instead, everything worked fine, no crashes, no errors. Since that time, I did not use parallel map and instead used futures. Recently I made a parallelization thing for solving exercises of Project Euler using multiple cores, so that some solutions are calculated faster. Maybe this can help or can be adapted to another use case: https://notabug.org/ZelphirKaltstahl/guile-project-euler-solutions/src/ebb19b11b465903105924adb6252f1e2ecf63859/lib/parallelism.scm#L11-L30 It expects ranges of things, which are called `segments` in the code. Usually ranges of numbers for Project Euler things. Here is the code to split a range into segments: https://notabug.org/ZelphirKaltstahl/guile-project-euler-solutions/src/ebb19b11b465903105924adb6252f1e2ecf63859/lib/segment.scm (Check any solution using it for an example.) So this might be a bit too specific for general parallel things, but I guess one could change the way futures are used in `run-in-parallel`, to fit any other purpose. Best regards, Zelphir -- repositories: https://notabug.org/ZelphirKaltstahl