From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id A95432ABF0 for ; Tue, 23 Oct 2018 03:12:22 -0400 (EDT) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MrMX0Req3s_y for ; Tue, 23 Oct 2018 03:12:22 -0400 (EDT) Received: from smtp52.i.mail.ru (smtp52.i.mail.ru [94.100.177.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTPS id 692C02AAEE for ; Tue, 23 Oct 2018 03:12:22 -0400 (EDT) Received: by smtp52.i.mail.ru with esmtpa (envelope-from ) id 1gEqrU-0001C8-IJ for tarantool-patches@freelists.org; Tue, 23 Oct 2018 10:12:20 +0300 Date: Tue, 23 Oct 2018 10:02:49 +0300 From: Konstantin Osipov Subject: [tarantool-patches] Re: [PATCH v2 09/11] vinyl: do not account zero dump bandwidth Message-ID: <20181023070249.GB9849@chai> References: <13fecfb17369a9d4819eb82115722c37245b2db0.1538155645.git.vdavydov.dev@gmail.com> <20181012132721.vbshvexo2igrhtur@esperanza> <20181016182518.GC5454@chai> <20181017084406.jt3lmsiawfsvbjar@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181017084406.jt3lmsiawfsvbjar@esperanza> Sender: tarantool-patches-bounce@freelists.org Errors-to: tarantool-patches-bounce@freelists.org Reply-To: tarantool-patches@freelists.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: tarantool-patches List-subscribe: List-owner: List-post: List-archive: To: tarantool-patches@freelists.org * Vladimir Davydov [18/10/17 12:14]: > On Tue, Oct 16, 2018 at 09:25:18PM +0300, Konstantin Osipov wrote: > > * Vladimir Davydov [18/10/12 21:23]: > > > Turns out this isn't enough. We'd better not account too small dumps, > > > because such dumps have too high overhead associated with file creation. > > > Our tests create a lot of small dumps using box.snapshot(). Taking them > > > into account may slow down the overall test execution time or even break > > > some tests. Let's ignore all dumps of size less than 1 MB for bandwidth > > > estimation. The new patch is below. > > > > Let's talk face to face, but this entire clutch seems to be > > becoming too huge with this patch. > > What's wrong with it? If you create a 100 MB file then the time it takes > to allocate an inode is negligible comparing to the write time. This is > a typical use case. However, if you create a 1 KB file, then you'll > spend much more time on inode bookkeeping than actually writing > anything. This is unlikely in practice (who'd write such small files?), > but this is done very often by our tests. This results in enabling > throttling and slowing down test execution time. Simply put, we need to disable throttling because things get worse when it's enabled. And we simply disable throttling considering this situation an edge case rather than try to understand what's wrong with our model that it makes things worse on edges. -- Konstantin Osipov, Moscow, Russia, +7 903 626 22 32 http://tarantool.io - www.twitter.com/kostja_osipov