From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60104) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ct3g5-0008Sd-U2 for qemu-devel@nongnu.org; Tue, 28 Mar 2017 22:49:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ct3g4-0004DJ-Pr for qemu-devel@nongnu.org; Tue, 28 Mar 2017 22:49:41 -0400 Date: Wed, 29 Mar 2017 13:24:49 +1100 From: David Gibson Message-ID: <20170329022449.GN21068@umbus.fritz.box> References: <1490189568-167621-1-git-send-email-imammedo@redhat.com> <1490189568-167621-6-git-send-email-imammedo@redhat.com> <20170328041920.GC21068@umbus.fritz.box> <20170328125310.4fa3da50@Igors-MacBook-Pro.local> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="yK/6QRnH3Zanb0EF" Content-Disposition: inline In-Reply-To: <20170328125310.4fa3da50@Igors-MacBook-Pro.local> Subject: Re: [Qemu-devel] [PATCH for-2.10 05/23] numa: move source of default CPUs to NUMA node mapping into boards List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, Eduardo Habkost , Peter Maydell , Andrew Jones , Eric Blake , Paolo Bonzini , Shannon Zhao , qemu-arm@nongnu.org, qemu-ppc@nongnu.org --yK/6QRnH3Zanb0EF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 28, 2017 at 12:53:10PM +0200, Igor Mammedov wrote: > On Tue, 28 Mar 2017 15:19:20 +1100 > David Gibson wrote: >=20 > > On Wed, Mar 22, 2017 at 02:32:30PM +0100, Igor Mammedov wrote: > > > Originally CPU threads were by default assigned in > > > round-robin fashion. However it was causing issues in > > > guest since CPU threads from the same socket/core could > > > be placed on different NUMA nodes. > > > Commit fb43b73b (pc: fix default VCPU to NUMA node mapping) > > > fixed it by grouping threads within a socket on the same node > > > introducing cpu_index_to_socket_id() callback and commit > > > 20bb648d (spapr: Fix default NUMA node allocation for threads) > > > reused callback to fix similar issues for SPAPR machine > > > even though socket doesn't make much sense there. > > >=20 > > > As result QEMU ended up having 3 default distribution rules > > > used by 3 targets /virt-arm, spapr, pc/. > > >=20 > > > In effort of moving NUMA mapping for CPUs into possible_cpus, > > > generalize default mapping in numa.c by making boards decide > > > on default mapping and let them explicitly tell generic > > > numa code to which node a CPU thread belongs to by replacing > > > cpu_index_to_socket_id() with @cpu_index_to_instance_props() > > > which provides default node_id assigned by board to specified > > > cpu_index. > > >=20 > > > Signed-off-by: Igor Mammedov [snip] > > > +static CpuInstanceProperties > > > +virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index) > > > +{ > > > + MachineClass *mc =3D MACHINE_GET_CLASS(ms); > > > + const CPUArchIdList *possible_cpus =3D mc->possible_cpu_arch_ids= (ms); > > > + > > > + assert(cpu_index < possible_cpus->len); > > > + return possible_cpus->cpus[cpu_index].props;; > > > +} > > > + > >=20 > > It seems a bit weird to have a machine specific hook to pull the > > property information when one way or another it's coming from the > > possible_cpus table, which is already constructed by a machine > > specific hook. Could we add a range or list of cpu_index values to > > each possible_cpus entry instead, and have a generic lookup of the > > right entry based on that? [snip] > > > -static unsigned pc_cpu_index_to_socket_id(unsigned cpu_index) > > > +static CpuInstanceProperties > > > +pc_cpu_index_to_props(MachineState *ms, unsigned cpu_index) > > > { > > > - X86CPUTopoInfo topo; > > > - x86_topo_ids_from_idx(smp_cores, smp_threads, cpu_index, > > > - &topo); > > > - return topo.pkg_id; > > > + MachineClass *mc =3D MACHINE_GET_CLASS(ms); > > > + const CPUArchIdList *possible_cpus =3D mc->possible_cpu_arch_ids= (ms); > > > + > > > + assert(cpu_index < possible_cpus->len); > > > + return possible_cpus->cpus[cpu_index].props;; > >=20 > > Since the pc and arm version of this are basically identical, I wonder > > if that should actually be the default implementation. If we need it > > at all. > ARM is still moving target and props are not really defined for it yet, > so I'd like to keep it separate for now and when it stabilizes we can thi= nk > about generalizing it. Fair enough. Any thoughts on my more general query above --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --yK/6QRnH3Zanb0EF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJY2xrvAAoJEGw4ysog2bOSlYAP/R3QY/plG35cKCa9j0vQOxem R6qBPoEojVFc7a+188bM8dR5SJi9HVAQ7qPvNtaPRlAAS/PqpaCpB9KdEJFlTO5D DmvXTM8QLisJ77LgZlbsSrmnkGjE8NrdeR9663vJ6jrHoTALpeG4eEsG1IZDw0A9 cLjREmmU3xDlGPSYJfR33qaHiy5MAXg7i7I34IsLUBZxBMqVPEDetJkY6l1Ci+xb vz56yQEg1BDyhlJbB5nz52noK+bIV1yOKhvGts/P6w5GMf0BmfNRxIfb0qJwYpNj qAZP8gT3bb0samK1drhmt+LkGxUnFRiHJhU5yNquRRISVQ7N+DX4TXON5HSheKZA JfkHgAgNB9n9XK9JzOBHoCbzIdzvRSQb0WGgB/e6NhG8zqTyyqxie0UhydjJKfdK 5xmaDtQNpd3EmADw4NeqmcmMNKsf4Os2pHta4A7XVsRVstGq5VHYjqPjUKuysC2Q l9B7EGJ/Sjmaf/gEXbct2o2qBPdk8jXLxJcHKYOuXCekFz9jsmGHa2vLrwKDOuQt KxbjbaXRRgq14AqKgr488ma82cZiyctWcnMjOLr1RlPXuF+urUDHL33JdEjBh9JP EFz73LN39b25VIJh67topZ1j9Tq1K0nXlm1MIcS7gOZ/r8h3vtAvLLqVeTc2quFw 9VdjJzoHYWK3xsETgnxo =KCgP -----END PGP SIGNATURE----- --yK/6QRnH3Zanb0EF--