From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40179) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGCK9-0006xE-1l for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:01:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YGCJz-0007aq-DJ for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:01:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42651) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGCJz-0007aW-6c for qemu-devel@nongnu.org; Tue, 27 Jan 2015 15:01:11 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t0RK197p032514 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Tue, 27 Jan 2015 15:01:10 -0500 Message-ID: <54C7EE83.8010506@redhat.com> Date: Tue, 27 Jan 2015 13:01:07 -0700 From: Eric Blake MIME-Version: 1.0 References: <1422288204-29271-1-git-send-email-mreitz@redhat.com> <1422288204-29271-11-git-send-email-mreitz@redhat.com> In-Reply-To: <1422288204-29271-11-git-send-email-mreitz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QH9vUfBHcasncKeDWqA4ubCtqgAIc1jid" 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: Max Reitz , qemu-devel@nongnu.org Cc: Kevin Wolf , Fam Zheng , Jeff Cody , Markus Armbruster , Stefan Hajnoczi , john@redhat.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --QH9vUfBHcasncKeDWqA4ubCtqgAIc1jid Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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. >=20 > 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. >=20 > 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(-) >=20 > 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; > =20 > + /* 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. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --QH9vUfBHcasncKeDWqA4ubCtqgAIc1jid Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJUx+6EAAoJEKeha0olJ0Nq+/kH/2oWn1rP0JTiMoOQf9CyWcdJ XkrA6XXofPLAmLfd+n3xDAvdxDbLeFEhEfQza/dRg42iEcpmVjO4oYMP1dAJ+duR DCdnmVyUM+35B9+otxZ1TtHJe0e4kbYXaZoUQU+xowsIHxV+ilXZ7r47dBeJ2Dqy Le/mwq5VKupO9vnPl4TiAmNQXf7PDIXrAzJrbwK5XXmHkQZasQ2BpFdCPKiWubfN FK1m1TOuuyYNJxz2HNKlCzRyvQHLBnhWwR4/e12QfZ4TAyK1eCdyOYcw35G9ZAoP V7f7JROXggZIbiqqPlNbMkRxTWZdk9IIRCahJJD1bKvUZlmXbV/tkWBUxezx2PU= =JD1y -----END PGP SIGNATURE----- --QH9vUfBHcasncKeDWqA4ubCtqgAIc1jid--