From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGCLs-0001B8-G2 for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:03:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YGCLl-0008Hn-GZ for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:03:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43445) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGCLl-0008Hf-7r for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:03:01 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t0RK30wO001179 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Tue, 27 Jan 2015 15:03:00 -0500 Message-ID: <54C7EEF2.6050100@redhat.com> Date: Tue, 27 Jan 2015 15:02:58 -0500 From: Max Reitz MIME-Version: 1.0 References: <1422288204-29271-1-git-send-email-mreitz@redhat.com> <1422288204-29271-11-git-send-email-mreitz@redhat.com> <54C7EE83.8010506@redhat.com> In-Reply-To: <54C7EE83.8010506@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 10/50] block: Remove wr_highest_offset from BlockAcctStats List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , qemu-devel@nongnu.org Cc: Kevin Wolf , Fam Zheng , Jeff Cody , Markus Armbruster , Stefan Hajnoczi , John Snow On 2015-01-27 at 15:01, Eric Blake wrote: > On 01/26/2015 09:02 AM, Max Reitz wrote: >> BlockAcctStats contains statistics about the data transferred from and >> to the device; wr_highest_offset does not fit in with the rest. >> >> Furthermore, those statistics are supposed to be specific for a certain >> device and not necessarily for a BDS (see the comment above >> bdrv_get_stats()); on the other hand, wr_highest_offset may be a rather >> important information to know for each BDS. When BlockAcctStats is >> finally removed from the BDS, we will want to keep wr_highest_offset in >> the BDS. > Yes, I recently did work in libvirt to expose wr_highest_offset of > backing images during block commit (qemu still isn't populating it on > images opened only for read, but the point remains that it is a > statistic tied to the BDS, not the BB). > > On the other hand, even the other statistics might make sense on both > BDS and BB level (at the BB level, how many bytes has the guest > read/written; at the BDS level, how many bytes were serviced by the > active layer vs. delegated to a backing layer). > > I'm not sure if we are set up for that fine of a level of reporting yet, > but we shouldn't make it hard to implement later. But for now, I agree > with separating the definite BDS-only stat, leaving the rest of the > struct usable for either BDS or BB. > >> Signed-off-by: Max Reitz >> --- >> block.c | 4 +++- >> block/accounting.c | 9 --------- >> block/qapi.c | 4 ++-- >> include/block/accounting.h | 3 --- >> include/block/block_int.h | 3 +++ >> 5 files changed, 8 insertions(+), 15 deletions(-) >> >> diff --git a/block.c b/block.c >> +++ b/include/block/block_int.h >> @@ -366,6 +366,9 @@ struct BlockDriverState { >> /* I/O stats (display with "info blockstats"). */ >> BlockAcctStats stats; >> >> + /* Highest sector index written to */ >> + uint64_t wr_highest_sector; > Umm, now would be a great time to track this in bytes instead of > sectors, if that is not too difficult to do. Fine with me, will do. (on a different note, please refer to the "RESEND" thread or replace john@redhat.com by jsnow@redhat.com in the CC list (my bad)) Max