From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f46.google.com (mail-pa0-f46.google.com [209.85.220.46]) by kanga.kvack.org (Postfix) with ESMTP id 885136B0038 for ; Thu, 29 Jan 2015 02:08:38 -0500 (EST) Received: by mail-pa0-f46.google.com with SMTP id lj1so35466443pab.5 for ; Wed, 28 Jan 2015 23:08:38 -0800 (PST) Received: from mail-pa0-x231.google.com (mail-pa0-x231.google.com. [2607:f8b0:400e:c03::231]) by mx.google.com with ESMTPS id hp4si4165689pbb.9.2015.01.28.23.08.37 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 28 Jan 2015 23:08:37 -0800 (PST) Received: by mail-pa0-f49.google.com with SMTP id fa1so35507938pad.8 for ; Wed, 28 Jan 2015 23:08:37 -0800 (PST) Date: Thu, 29 Jan 2015 16:08:35 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH v1 2/2] zram: remove init_lock in zram_make_request Message-ID: <20150129070835.GD2555@swordfish> References: <1422432945-6764-1-git-send-email-minchan@kernel.org> <1422432945-6764-2-git-send-email-minchan@kernel.org> <20150128145651.GB965@swordfish> <20150128233343.GC4706@blaptop> <20150129020139.GB9672@blaptop> <20150129022241.GA2555@swordfish> <20150129052827.GB25462@blaptop> <20150129060604.GC2555@swordfish> <20150129063505.GA32331@blaptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150129063505.GA32331@blaptop> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Sergey Senozhatsky , Sergey Senozhatsky , Andrew Morton , "linux-kernel@vger.kernel.org" , Linux-MM , Nitin Gupta , Jerome Marchand , Ganesh Mahendran On (01/29/15 15:35), Minchan Kim wrote: > > As you told, the data was not stable. > yes. fread test was always slower, and the rest was mostly slower. > Anyway, when I read down_read implementation, it's one atomic instruction. > Hmm, it seems te be better for srcu_read_lock which does more things. > srcu looks havier, agree. > But I guessed most of overhead are from [de]compression, memcpy, clear_page > That's why I guessed we don't have measurable difference from that. > What's the data pattern if you use iozone? by "data pattern" you mean usage scenario? well, I usually use zram for `make -jX', where X=[4..N]. so N concurrent read-write ops scenario. -ss > I guess it's really simple pattern compressor can do fast. I used /dev/sda > for dd write so more realistic data. Anyway, if we has 10% regression even if > the data is simple, I never want to merge it. > I will test it carefully and if it turns out lots regression, > surely, I will not go with this and send the original patch again. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org