From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43023) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cfqA7-0007AQ-2i for qemu-devel@nongnu.org; Mon, 20 Feb 2017 10:46:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cfqA6-000608-90 for qemu-devel@nongnu.org; Mon, 20 Feb 2017 10:46:03 -0500 Date: Mon, 20 Feb 2017 16:45:54 +0100 From: Kevin Wolf Message-ID: <20170220154554.GF4814@noname.redhat.com> References: <20170220153012.GK21255@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="NklN7DEeGtkPCoo3" Content-Disposition: inline In-Reply-To: <20170220153012.GK21255@stefanha-x1.localdomain> Subject: Re: [Qemu-devel] blockdev-add I/O throttling parameters List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Max Reitz , Eric Blake , qemu-block@nongnu.org, qemu-devel@nongnu.org, berto@igalia.com --NklN7DEeGtkPCoo3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 20.02.2017 um 16:30 hat Stefan Hajnoczi geschrieben: > I/O throttling parameters are missing from blockdev-add. Is this > intentional? >=20 > I can imagine two solutions that do not need these parameters in > blockdev-add: >=20 > 1. I/O throttling is implemented by a BlockDriver. Users are expected > to create the BDS themselves. This is a little awkward since > query-block *does* include the throttling parameters in its output > and we must preserve this behavior for existing users. >=20 > 2. block_set_io_throttle must be used after blockdev-add. Suboptimal > because issuing two commands is not atomic (use transaction?). >=20 > Thoughts? The existing I/O throttling code is working on BlockBackends, but blockdev-add creates BlockDriverStates. So it can't possibly add throttling parameters. The currently recommended solution block_set_io_throttle. The other option to control BB level thorttling would be to add qdev properties to the block devices. In the long term, I think going with 1. and moving throttling to the block node level is the much nicer (and more flexible) option. Kevin --NklN7DEeGtkPCoo3 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJYqw8yAAoJEH8JsnLIjy/WdWwP/AyA4NopGMl49Y2wXAzM0BGh KC7Bs/Q8Vx+lB3T4PwUayw5vplNN5PQi55R1VOQOXsNVjcIlfZ0zQ4FoxiVV09fn B1ObUr89dmJB0QF+vWxWp5l59NwAaXwYmSxR1qJMFT8Gd4y64/0+O0anu8oM047e NPHqOlQ44BhYyGk2tSfIlJd9uM5jKOv1iCy8p6N1FDZfH57/D9gS3gricMRkmJs8 FMNCxSrtdX26E4okScHu/PIS8+Dh+FbAaB6MdigJ4CTkBLRmLuM21jV/9FAOB2Pa /YI/R81jh1YYnuKNr0Zw9MlE/Mfl5WDe8TC+foQNFW4NTzSwy25124b2BU/mkwJV TmmF1vjHCI0SOdMeE18An7ma1b+2KGQrVco8m+rgbUC6jETLZFEpa2JvhGjHQFO7 5ZproaYPSrVVgQyuGa2RS38bAAQkPsIBzkx+TuePoxvA0lbDfUN006BVXlH/84hn vMY+WmWO+8QQwTOenneYAII+BYI/nfQQczODAeo+QrZAdHyHz9z/litfyWI9ctT2 reOyNqRRvHUaTM8S2SnI/bJblB2c2LaU/cLGTNyiUR8J4OXR0Y3kZRgLkWooJniL C5aNExqfFXJSFW4eTzT4+hJkWwUkrr2S7VqtnuVYbTRIGt04gjLNC6+nuUP2uHdy zUr8jzrHtcKOg4MfigHe =3/CI -----END PGP SIGNATURE----- --NklN7DEeGtkPCoo3--