From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 16 May 2016 09:47:41 +0200 From: Jan Kara To: Jens Axboe Cc: Jan Kara , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, dchinner@redhat.com, sedat.dilek@gmail.com Subject: Re: [PATCHSET v5] Make background writeback great again for the first time Message-ID: <20160516074741.GA12026@quack2.suse.cz> References: <1461686131-22999-1-git-send-email-axboe@fb.com> <20160427180105.GA17362@quack2.suse.cz> <5721021E.8060006@fb.com> <20160427203708.GA25397@kernel.dk> <20160427205915.GC25397@kernel.dk> <20160428115401.GD17362@quack2.suse.cz> <57225A91.50002@kernel.dk> <20160503121719.GA25436@quack2.suse.cz> <20160511163608.GG14744@quack2.suse.cz> <57361CF6.3040202@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <57361CF6.3040202@kernel.dk> List-ID: On Fri 13-05-16 12:29:10, Jens Axboe wrote: > Thanks Jan, this is great and super useful! I'm revamping certain parts of > it to deal with write back caching better, and I'll take a look at the > regressions that you reported. > > What kind of SSD is this? I'm assuming it's SATA (QD=32), and then it would > probably be a safe assumption that it's flagging itself as having a volatile > write back cache, would that be a correct assumption? Yes, it is SATA with writeback cache. > Are you using scsi-mq, or do you have an IO scheduler attached to it? The disk was using IO scheduler, however at this point I'm not 100% sure which scheduler (deadline or cfq) was the default one for the distro that was installed. The machine is currently testing something else so I cannot reinstall it and check. Maybe I can rerun some tests later in the week when the machine gets freed with scsi-mq or deadline IO scheduler so that we have 100% certain config. Honza -- Jan Kara SUSE Labs, CR