From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: raid0 vs. mkfs Date: Mon, 28 Nov 2016 01:00:53 -0800 Message-ID: <20161128090053.GA9393@infradead.org> References: <56c83c4e-d451-07e5-88e2-40b085d8681c@scylladb.com> <87oa108a1x.fsf@notabene.neil.brown.name> <286a5fc1-eda3-0421-a88e-b03c09403259@scylladb.com> <87inr880au.fsf@notabene.neil.brown.name> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Avi Kivity Cc: NeilBrown , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, Nov 28, 2016 at 10:58:24AM +0200, Avi Kivity wrote: > What I guess is happening is that since the NVMe queue depth is so high, and > request the driver receives is sent immediately to the disk and there is > nothing to merge it to. That could indicate the absence of plugging, or > just a reluctance to merge TRIMs. That is exactly the case, and it's also an issue with online trim. I have work in progress block layer trim patches that always plug trims and have various TRIM merge improvements including support for ranged TRIMs. It needs a bit more work, but I hope I can post it later this week.