From: Akira Hayakawa Subject: Re: [dm-devel] [PATCH v2] staging: writeboost: Add dm-writeboost Date: Fri, 12 Dec 2014 18:35:32 +0900 Message-ID: <548AB6E4.2020302@gmail.com> References: <54883195.1060304@gmail.com> <20141211152626.GA8196@redhat.com> <548A39E7.80508@gmail.com> <548AB172.4000103@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <548AB172.4000103@acm.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: bvanassche@acm.org Cc: thornber@redhat.com, snitzer@redhat.com, gregkh@linuxfoundation.org, driverdev-devel@linuxdriverproject.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com List-Id: dm-devel.ids On 12/12/14 6:12 PM, Bart Van Assche wrote: > This is the first time I see someone claiming that reducing the request size improves performance. I don't know any SSD model for which splitting requests improves performance. Writeboost batches number of writes into a log (that is 512KB large) and submits to SSD which maximizes the throughput and the lifetime of the SSD. I think you fairly misunderstand how Writeboost works. - Akira