From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Anup Patel <Anup.Patel@wdc.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
"qemu-riscv@nongnu.org" <qemu-riscv@nongnu.org>,
Eduardo Habkost <ehabkost@redhat.com>,
Sagar Karandikar <sagark@eecs.berkeley.edu>,
Anup Patel <anup@brainfault.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Atish Patra <Atish.Patra@wdc.com>,
Alistair Francis <Alistair.Francis@wdc.com>,
Palmer Dabbelt <palmer@dabbelt.com>
Subject: Re: [PATCH v2 1/5] hw: Add sockets_specified field in CpuTopology
Date: Wed, 27 May 2020 10:51:23 +0100 [thread overview]
Message-ID: <20200527095123.GH2665520@redhat.com> (raw)
In-Reply-To: <DM6PR04MB6201A8060078D3539BFDE3688DB10@DM6PR04MB6201.namprd04.prod.outlook.com>
On Wed, May 27, 2020 at 09:48:39AM +0000, Anup Patel wrote:
>
>
> > -----Original Message-----
> > From: Daniel P. Berrangé <berrange@redhat.com>
> > Sent: 27 May 2020 14:16
> > To: Anup Patel <Anup.Patel@wdc.com>
> > Cc: Eduardo Habkost <ehabkost@redhat.com>; Marcel Apfelbaum
> > <marcel.apfelbaum@gmail.com>; Peter Maydell <peter.maydell@linaro.org>;
> > Palmer Dabbelt <palmer@dabbelt.com>; Alistair Francis
> > <Alistair.Francis@wdc.com>; Sagar Karandikar <sagark@eecs.berkeley.edu>;
> > Atish Patra <Atish.Patra@wdc.com>; qemu-riscv@nongnu.org; qemu-
> > devel@nongnu.org; Anup Patel <anup@brainfault.org>
> > Subject: Re: [PATCH v2 1/5] hw: Add sockets_specified field in CpuTopology
> >
> > On Wed, May 27, 2020 at 11:12:22AM +0530, Anup Patel wrote:
> > > When "sockets" sub-option of "-smp" option is not specified, the
> > > smp_parse() function will assume one CPU per-socket and set the number
> > > of sockets equal to number of CPUs.
> > >
> > > This is counter-intuitive and we should allow machine emulation to
> > > decide default number of sockets when "sockets" sub-option is not
> > > specified.
> >
> > I don't agree with this. Having the semantics of the -smp option be the same
> > across all targets/machines *is* intuitive. Changing semantics of -smp per-
> > machine will create a worse experiance for people configuring QEMU as the
> > configuration will mean different things depending on the machine choce.
>
> Okay then why don't we default to sockets=1 in smp_parse() when "sockets"
> sub-options is not specified ?? This will make it uniform across machines.
>
> Is there a reason to by default have sockets=max_cpus ??
IIUC both of these questions are due to backwards compatibility with
pre-existing QEMU versions.
Regards,
Daniel
--
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next prev parent reply other threads:[~2020-05-27 9:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 5:42 [PATCH v2 0/5] RISC-V multi-socket support Anup Patel
2020-05-27 5:42 ` [PATCH v2 1/5] hw: Add sockets_specified field in CpuTopology Anup Patel
2020-05-27 8:45 ` Daniel P. Berrangé
2020-05-27 9:48 ` Anup Patel
2020-05-27 9:51 ` Daniel P. Berrangé [this message]
2020-05-27 10:01 ` Anup Patel
2020-05-27 10:42 ` Daniel P. Berrangé
2020-05-27 10:55 ` Anup Patel
2020-05-27 5:42 ` [PATCH v2 2/5] hw/riscv: Allow creating multiple instances of CLINT Anup Patel
2020-05-27 5:42 ` [PATCH v2 3/5] hw/riscv: spike: Allow creating multiple sockets Anup Patel
2020-05-27 5:42 ` [PATCH v2 4/5] hw/riscv: Allow creating multiple instances of PLIC Anup Patel
2020-05-27 5:42 ` [PATCH v2 5/5] hw/riscv: virt: Allow creating multiple sockets Anup Patel
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