From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751494AbaANOMX (ORCPT ); Tue, 14 Jan 2014 09:12:23 -0500 Received: from mail-ee0-f42.google.com ([74.125.83.42]:36864 "EHLO mail-ee0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751329AbaANOMU (ORCPT ); Tue, 14 Jan 2014 09:12:20 -0500 Date: Tue, 14 Jan 2014 17:09:23 +0300 From: Sergey Senozhatsky To: Jerome Marchand Cc: Minchan Kim , Nitin Gupta , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] zram: rework reported to end-user zram statistics Message-ID: <20140114140923.GD2226@swordfish.minsk.epam.com> References: <1389692260-4421-1-git-send-email-sergey.senozhatsky@gmail.com> <1389692260-4421-4-git-send-email-sergey.senozhatsky@gmail.com> <52D513BD.7000800@redhat.com> <20140114111012.GC2180@swordfish.minsk.epam.com> <52D53F11.3090005@redhat.com> <20140114135355.GC2226@swordfish.minsk.epam.com> <52D54375.8070706@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52D54375.8070706@redhat.com> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (01/14/14 15:02), Jerome Marchand wrote: > On 01/14/2014 02:53 PM, Sergey Senozhatsky wrote: > > On (01/14/14 14:43), Jerome Marchand wrote: > > [..] > >>>> > >>>> That's weird: good/bad_compress are accounted, but it seems to me that > >>>> they are to never used in any way. If so, there is indeed no reason to > >>>> keep them. > >>>> > >>>> > >>>>> Account each sub-request > >>>>> compression size so we can calculate real device compression ratio. > >>>> > >>>> Your patch doesn't change the way pages_stored and compr[essed]_size > >>>> are accounted. What does your patch change that allow us to calculate > >>>> the "real" compression ratio? > >>>> > >>>>> > >>>>> 4) reported zram stats: > >>>>> - num_writes -- number of writes > >>>>> - num_reads -- number of reads > >>>>> - pages_stored -- number of pages currently stored > >>>>> - compressed_size -- compressed size of pages stored > >>>> > >>>> Wouldn't it be more practical to report the original and compressed > >>>> data sizes using the same units as it is currently done? > >>>> > >>> > >>> hm, do we really need pages_stored stats? what kind of unseful information it > >>> shows to end user?.. perhaps, it's better to replace it with accounted passed > >>> bvec->bv_len (as uncompressed_size). > >>> > >> > >> That's really going to complicates things. We would need to keep track > >> of which sectors of a particular page has been written to. It's much > >> easier to keep current page granularity and consider any partial I/O > >> as an whole page I/O. > >> > > > > fair enough. thank you. > > > > 2/3 and 3/3 were changed according to your comments: > > - 2/3 drop READA check > > - 3/3 update commit message. > > > > ready to re-publish. may I add your ACK to all 3 patches or just to 1/3? > > The READA thing was my only concern for 2/3, so yes for this one. > Concerning the third patch, I'd like to see what other people think > about which stats we want to report. > good. so I hold on for a bit to minimize the traffic and see what other people think. thank you. -ss > >>> > >>>> Jerome > >>>> > >>>>> - pages_zero -- number of zero filled pages > >>>>> - failed_read -- number of failed reads > >>>>> - failed_writes -- can happen when memory is too low > >>>>> - invalid_io -- non-page-aligned I/O requests > >>>>> - notify_free -- number of swap slot free notifications > >>>>> - memory_used -- zs pool zs_get_total_size_bytes() > >>>>> > >>>>> Signed-off-by: Sergey Senozhatsky > >> > >> >