X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:reply-to :references:mime-version:content-type:in-reply-to; q=dns; s= default; b=n3sZJUrlFhiRL+ytasZTSKA0mnAnT2PbwGHGW8LoZlDb9GL2vYSfX b9qlNb9v8mMtBmifEkZGaK89eyt/haPXMR9w4hsMgZqK++anD7ux4AYN/hRspsaV jXlwR3qf43fjonwN52Yk3LRPTeFjB5PWHCMaIITtiGV1WtBLkePy1s= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:reply-to :references:mime-version:content-type:in-reply-to; s=default; bh=k+tO1khzIoU/Ga8nhdf9dKuAeAg=; b=jcMebW9+y+SQyttHqoNf5Tjuf6zM H9FVCWVipwa7sBQ2Cyf6LJToFBQiHrE6YJ/ACXBvBl+a04TGGkG6HlMVewKiIhAR DR+RHLQg4cgXUOhkp45u5tXZiyGTouiNtugNfInLZyNX7zwBQTqrwd8p5BplGdiz lgV/Y+SGUlEzqmo= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-99.1 required=5.0 tests=AWL,BAYES_05,GOOD_FROM_CORINNA_CYGWIN,KAM_LAZY_DOMAIN_SECURITY,RCVD_IN_BRBL_LASTEXT,RCVD_IN_DNSWL_LOW,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=busy, reserves, zerofilling, i72600k X-HELO: drew.franken.de Date: Fri, 12 Jan 2018 15:33:39 +0100 From: Corinna Vinschen To: cygwin AT cygwin DOT com Subject: Re: calloc speed difference Message-ID: <20180112143339.GE24623@calimero.vinschen.de> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <46515148-9f8e-6eae-69f9-9bf20921097a AT t-online DOT de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RnlQjJ0d97Da+TV1" Content-Disposition: inline In-Reply-To: <46515148-9f8e-6eae-69f9-9bf20921097a@t-online.de> User-Agent: Mutt/1.9.1 (2017-09-22) --RnlQjJ0d97Da+TV1 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Jan 12 15:06, Christian Franke wrote: > Lee wrote: > > Why is the cygwin gcc calloc so much slower than the > > i686-w64-mingw32-gcc calloc? > > 1:12 vs 0:11 > >=20 > > $cat calloc-test.c > > #include > > #include > > #define ALLOCATION_SIZE (100 * 1024 * 1024) > > int main (int argc, char *argv[]) { > > for (int i =3D 0; i < 10000; i++) { > > void *temp =3D calloc(ALLOCATION_SIZE, 1); > > if ( temp =3D=3D NULL ) { > > printf("drat! calloc returned NULL\n"); > > return 1; > > } > > free(temp); > > } > > return 0; > > } > >=20 >=20 > Could reproduce the difference on an older i7-2600K machine: >=20 > Cygwin: ~20s > MinGW: ~4s >=20 > Timing [cm]alloc() calls without actually using the allocated memory might > produce misleading results due to lazy page allocation and/or zero-fillin= g. >=20 > MinGW binaries use calloc() from msvcrt.dll. This calloc() does not call > malloc() and then memset(). It directly calls: >=20 > mem =3D HeapAlloc(_crtheap, HEAP_ZERO_MEMORY, size); >=20 > which possibly only reserves allocate-and-zero-fill-on-demand pages for > later. >=20 > Cygwin's calloc() is different. But then again, Cygwin's malloc *is* slow, particulary in memory-demanding multi-threaded scenarios since that serializes all malloc/free calls. The memory handling within Cygwin is tricky. Attempts to replace good old dlmalloc with a fresher jemalloc or ptmalloc failed, but that only means the developer (i.e., me, in case of ptmalloc) was too lazy... busy! I mean busy... to pull this through. Having said that, if somebody would like to take a stab at replacing dlmalloc with something leaner, I would be very happy and assist as much as I can. Corinna --=20 Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat --RnlQjJ0d97Da+TV1 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEoVYPmneWZnwT6kwF9TYGna5ET6AFAlpYx0MACgkQ9TYGna5E T6DB/g/9EHqVffSQL9YzEex8xo3m/f6wfh4ua/yKkass6YAvFFcWeSln04x0adfp xuklqxXadPHW7B4+Z8Smc9M5EeO63ZEEh++8ryEqrjzSI0GC/j+IKVsLRj/IWmty 6oAXXi4FXZLvDcb8b1ivYmuELE5/cvfMAqQY7esp1b4TYJJuxIzJy4hba4NH5JHx 3Z4rWXT+76+Cghcn7FiecjYAUecGaAD9r9AElT3JQcBuOd6aRac+2jke5PDJ90ue rHH0Ce862RDatMwvL/TXABiaYEr5fDrGYr118vJw2VbwuqEQm+WePHG/T6tNRGsQ Yhncrvtz0V7PxXwspQjXEQ8qD96lKVotWJt/QeoG9g818Z3/b7V59Np9NiGZEtBe gGYqQYKgoSeWTmojalNHsE09AhHwkj3XqGf2MQd5o+lbeYpbkgQeEcybt4kPHiOy bjVvopBkMXM905vzi4L8N7RtgTAsYSLlbgJVnF2Ntlh3ZDLAHp/JlN/G6YbJkCKn u33MA88nGPqKSZoEKsfpbDKpuCTBfRl5rdoss5rr5LuMXT4tT2Y2rUUmicpwPkoT yfRT3uHYvikuEDixZWdb5idmOiOZL9RRes6qI1mNavJiR5axgGiFr0RL4qt2uohn UMlNniLsgFUKaKUGNcKC9yBVJER8547C+A+7ih/RPVRN4rfcDWg= =LcJB -----END PGP SIGNATURE----- --RnlQjJ0d97Da+TV1--