From owner-svn-src-head@freebsd.org Fri Oct 30 22:23:01 2015 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id ABB6CA210C8; Fri, 30 Oct 2015 22:23:01 +0000 (UTC) (envelope-from bdrewery@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:1900:2254:206c::16:87]) by mx1.freebsd.org (Postfix) with ESMTP id 943CA10A9; Fri, 30 Oct 2015 22:23:01 +0000 (UTC) (envelope-from bdrewery@FreeBSD.org) Received: from mail.xzibition.com (localhost [IPv6:::1]) by freefall.freebsd.org (Postfix) with ESMTP id 8CDF717F0; Fri, 30 Oct 2015 22:23:01 +0000 (UTC) (envelope-from bdrewery@FreeBSD.org) Received: from mail.xzibition.com (localhost [172.31.3.2]) by mail.xzibition.com (Postfix) with ESMTP id 46EB710693; Fri, 30 Oct 2015 22:23:01 +0000 (UTC) X-Virus-Scanned: amavisd-new at mail.xzibition.com Received: from mail.xzibition.com ([172.31.3.2]) by mail.xzibition.com (mail.xzibition.com [172.31.3.2]) (amavisd-new, port 10026) with LMTP id 7ckM51s8x3IB; Fri, 30 Oct 2015 22:22:58 +0000 (UTC) Subject: Re: svn commit: r289279 - in head/sys: kern vm DKIM-Filter: OpenDKIM Filter v2.9.2 mail.xzibition.com 1DC2E1068E To: Jeff Roberson , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201510140210.t9E2A79H056595@repo.freebsd.org> From: Bryan Drewery Openpgp: id=F9173CB2C3AAEA7A5C8A1F0935D771BB6E4697CF; url=http://www.shatow.net/bryan/bryan2.asc Organization: FreeBSD Message-ID: <5633EDC4.4050907@FreeBSD.org> Date: Fri, 30 Oct 2015 15:23:00 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <201510140210.t9E2A79H056595@repo.freebsd.org> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="8hdwCcLAuVUU2moDgCxWjfI7lIqvnAe5h" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Oct 2015 22:23:01 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --8hdwCcLAuVUU2moDgCxWjfI7lIqvnAe5h Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 10/13/2015 7:10 PM, Jeff Roberson wrote: > Author: jeff > Date: Wed Oct 14 02:10:07 2015 > New Revision: 289279 > URL: https://svnweb.freebsd.org/changeset/base/289279 >=20 > Log: > Parallelize the buffer cache and rewrite getnewbuf(). This results i= n a > 8x performance improvement in a micro benchmark on a 4 socket machine= =2E > =20 > - Get buffer headers from a per-cpu uma cache that sits in from of t= he > free queue. > - Use a per-cpu quantum cache in vmem to eliminate contention for kv= a. > - Use multiple clean queues according to buffer cache size to elimin= ate > clean queue lock contention. > - Introduce a bufspace daemon that attempts to prevent getnewbuf() c= allers > from blocking or doing direct recycling. > - Close some bufspace allocation races that could lead to endless > recycling. > - Further the transition to a more modern style of small functions g= rouped > by prefix in order to improve growing complexity. > =20 > Sponsored by: EMC / Isilon > Reviewed by: kib > Tested by: pho >=20 > Modified: > head/sys/kern/vfs_bio.c > head/sys/vm/vm_init.c =2E.. > +static void > +bufkva_reclaim(vmem_t *vmem, int flags) > +{ > + int i; > + > + for (i =3D 0; i < 5; i++) What is the significance of '5' here? It seems arbitrary without comments or a tunable that other code is based on. > + if (buf_scan(true) !=3D 0) > + break; > + return; > +} --=20 Regards, Bryan Drewery --8hdwCcLAuVUU2moDgCxWjfI7lIqvnAe5h Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBAgAGBQJWM+3EAAoJEDXXcbtuRpfPDk4H/juqqo5tgykglYFAfPHK3rsn Yoqn/61xEX8hYoZ5hEE3vJR+gDrwu/CCi+ls8jPOj3q/DxPtI8NK9XVhbAgaGhfm wO9unNtVmjb2UDaEH6iUIelPqDBWUP99h/K39Pw8vGpWf5l5+D864tiRxykf6WQk dWRAA13iq0vzFUVBbwilZL5ETTtg0fDxcXflJ++Hy6PFttqmDR6aX5J8/XLdkTFn WhWqo3Afm93ALa0eCm/daJNX6oW/VdahuuuD9s+M1eVSlE6YVsdagBj9dFLkO4kw IQsfBYGzSOB7NX+swQXPJBtN8PN0XdTs7Rac3ClhmQQdMjeJChsalWkwsGGh4Cs= =hpf0 -----END PGP SIGNATURE----- --8hdwCcLAuVUU2moDgCxWjfI7lIqvnAe5h--