From owner-svn-src-head@FreeBSD.ORG Thu Sep 4 14:49:14 2014 Return-Path: Delivered-To: svn-src-head@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 4C027EEC; Thu, 4 Sep 2014 14:49:14 +0000 (UTC) Received: from mail.lifanov.com (mail.lifanov.com [206.125.175.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 24D84123F; Thu, 4 Sep 2014 14:49:13 +0000 (UTC) Received: by mail.lifanov.com (Postfix, from userid 58) id 345B11B30EA; Thu, 4 Sep 2014 10:49:13 -0400 (EDT) Received: from [127.0.0.1] (vnat004.nandomedia.com [166.108.31.68]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.lifanov.com (Postfix) with ESMTPSA id B73481B30E5; Thu, 4 Sep 2014 10:49:09 -0400 (EDT) Message-ID: <54087BE4.6030601@mail.lifanov.com> Date: Thu, 04 Sep 2014 10:49:08 -0400 From: Nikolai Lifanov User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Steven Hartland , Andriy Gapon , John Baldwin Subject: Re: svn commit: r270759 - in head/sys: cddl/compat/opensolaris/kern cddl/compat/opensolaris/sys cddl/contrib/opensolaris/uts/common/fs/zfs vm References: <201408281950.s7SJo90I047213@svn.freebsd.org> <169C94ED141B435BACEADB04A4824717@multiplay.co.uk> <54072E20.10802@mail.lifanov.com> <2230377.GgKARkJyaG@ralph.baldwin.cx> <540778A2.3080809@mail.lifanov.com> <5407816B.9000401@FreeBSD.org> <86292055B4114529874B693EEB441CB6@multiplay.co.uk> In-Reply-To: <86292055B4114529874B693EEB441CB6@multiplay.co.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Thu, 04 Sep 2014 15:35:50 +0000 Cc: src-committers@FreeBSD.org, Peter Wemm , Alan Cox , svn-src-all@FreeBSD.org, Dmitry Morozovsky , "Matthew D. Fuller" , svn-src-head@FreeBSD.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.18-1 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: Thu, 04 Sep 2014 14:49:14 -0000 On 09/03/14 21:18, Steven Hartland wrote: > > ----- Original Message ----- From: "Andriy Gapon" > > >> on 03/09/2014 23:22 Nikolai Lifanov said the following: >>> On 09/03/14 15:22, John Baldwin wrote: >>>> On Wednesday, September 03, 2014 11:05:04 AM Nikolai Lifanov wrote: >>>>> On 09/03/14 04:09, Steven Hartland wrote: >>>>>> I'm looking to MFC this change so wanted to check if >>>>>> anyone had an final feedback / objections? >>>>>> >>>>>> I know we currently have Alan's feedback on changing >>>>>> the #ifdef __i386__ to #ifndef UMA_MD_SMALL_ALLOC >>>>>> which sounds sensible but waiting Peter to comment on. >>>>>> >>>>>> Regards >>>>>> Steve >>>>> >>>>> I have no technical input, but this change improves ARC usefulness for >>>>> me quite a bit. I would like to see the improvement in 10-STABLE. >>>> >>>> Can you verify that the current 10-STABLE (as of today) with all the >>>> various pagedaemon fixes still has ARC issues for your workload? >>>> >>> >>> It doesn't have any issues, but I noticed the improvement on CURRENT. I >>> observed that just after this change, my package builder is much more >>> likely to retain MFU and not evict useful things from there (the port >>> tree) after large builds. >>> However, I run a lot more 10.0-RELEASE than CURRENT and I would like to >>> see this improvement release-bound. >>> >>> I would be happy to test this on 10-STABLE if you think that this is >>> relevant. >> >> >> As noted before, unfortunately, this commit (plus its fixups) contains >> at least >> two related but distinct changes. So, to separate the wheat from the >> chaff, >> could you please try to comment out the following block in >> sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c, function >> arc_reclaim_needed: >> >> if (kmem_free_count() < zfs_arc_free_target) { >> DTRACE_PROBE2(arc__reclaim_freetarget, uint64_t, >> kmem_free_count(), uint64_t, zfs_arc_free_target); >> return (1); >> } >> >> Alternatively, I think that the same effect can be achieved by setting >> sysctl >> vfs.zfs.arc_free_target to the same value as vm.stats.vm.v_free_min. > > Thats correct that would achieve the same thing. > >> It's interesting to me whether you would still see the better >> performance or if >> that improvement would be undone. > > Indeed that would be interesting, but we might find that its quite > memory size > dependent given the scaling so confirming HW details would be nice too. > > I'd also be interested to know who wins the free race between the VM and > ARC > when using that value. > > For those following this thread but not the review, I've added some > additional > information there which you might be interested in: > https://reviews.freebsd.org/D702 > > Regards > Steve Just an update: I'm in the middle of testing this. I have to finish a large bulk build to observe the behavior one way or another. I have 32G of physical memory and 2x16G dedicated swap SSDs (L2ARC wasn't very useful, but I should probably retest this) on this machine. My ARC is usually at 14G with ~5G of MFU full of things I benefit from keeping there (port trees, base jails). Builds themselves happen in tmpfs and I usually have around 1.5G - 4G "Free" memory (unless building something like pypy). - Nikolai Lifanov