From: "wangyanan (Y)" <wangyanan55@huawei.com>
To: "Andrew Jones" <drjones@redhat.com>,
"Daniel P . Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
wanghaibin.wang@huawei.com,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Igor Mammedov <imammedo@redhat.com>,
yuzenghui@huawei.com, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC PATCH 4/6] machine: Uniformly use maxcpus to calculate the missing values
Date: Tue, 13 Jul 2021 15:49:07 +0800 [thread overview]
Message-ID: <1b76cfaa-a259-7ed4-635e-173bc3aa018c@huawei.com> (raw)
In-Reply-To: <20210702100739.13672-5-wangyanan55@huawei.com>
On 2021/7/2 18:07, Yanan Wang wrote:
> We are currently using maxcpus to calculate value of sockets but using
> cpus to calculate value of cores/threads. This makes cmdlines like
> "-smp 8,maxcpus=12,cores=4" work while "-smp 8,maxcpus=12,sockets=3"
> break the invalid cpu topology check.
>
> This patch allows us to uniformly use maxcpus to calculate the missing
> values. Also the if branch of "cpus == 0 || sockets == 0" was splited
> into branches of "cpus == 0" and "sockets == 0" so that we can clearly
> figure out that we are parsing -smp cmdlines with a preference of cpus
> over sockets over cores over threads.
BTW, after this patch, configs like:
-smp maxcpus=16 --> -smp 1,sockets=1,cores=1,threads=1,maxcpus=16
-smp sockets=2,maxcpus=16 --> -smp 2,sockets=2,cores=1,threads=1,maxcpus=16
......
still can not work. So I suggest to use the parameters computed by
maxcpus to calculate
the value of cpus if it's omitted. The diff based on this patch is:
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 93c5227920..924c48fd43 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -757,13 +757,7 @@ static void smp_parse(MachineState *ms,
SMPConfiguration *config, Error **errp)
/* compute missing values, prefer sockets over cores over threads */
maxcpus = maxcpus > 0 ? maxcpus : cpus;
- if (cpus == 0) {
- sockets = sockets > 0 ? sockets : 1;
- cores = cores > 0 ? cores : 1;
- threads = threads > 0 ? threads : 1;
- cpus = sockets * cores * threads;
- maxcpus = maxcpus > 0 ? maxcpus : cpus;
- } else if (sockets == 0) {
+ if (sockets == 0) {
cores = cores > 0 ? cores : 1;
threads = threads > 0 ? threads : 1;
sockets = maxcpus / (cores * threads);
@@ -777,6 +771,9 @@ static void smp_parse(MachineState *ms,
SMPConfiguration *config, Error **errp)
threads = threads > 0 ? threads : 1;
}
+ cpus = cpus > 0 ? cpus : sockets * cores * threads;
+ maxcpus = maxcpus > 0 ? maxcpus : cpus;
+
if (sockets * cores * threads < cpus) {
error_setg(errp, "cpu topology: "
"sockets (%u) * cores (%u) * threads (%u) < "
Thanks,
Yanan
.
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
> hw/core/machine.c | 36 +++++++++++++++++++-----------------
> hw/i386/pc.c | 37 +++++++++++++++++++------------------
> 2 files changed, 38 insertions(+), 35 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 1e194677cd..58882835be 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -752,34 +752,36 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
> }
>
> /* compute missing values, prefer sockets over cores over threads */
> - if (cpus == 0 || sockets == 0) {
> + maxcpus = maxcpus > 0 ? maxcpus : cpus;
> +
> + if (cpus == 0) {
> + sockets = sockets > 0 ? sockets : 1;
> cores = cores > 0 ? cores : 1;
> threads = threads > 0 ? threads : 1;
> - if (cpus == 0) {
> - sockets = sockets > 0 ? sockets : 1;
> - cpus = cores * threads * sockets;
> - } else {
> - maxcpus = maxcpus > 0 ? maxcpus : cpus;
> - sockets = maxcpus / (cores * threads);
> - sockets = sockets > 0 ? sockets : 1;
> - }
> + cpus = sockets * cores * threads;
> + maxcpus = maxcpus > 0 ? maxcpus : cpus;
> + } else if (sockets == 0) {
> + cores = cores > 0 ? cores : 1;
> + threads = threads > 0 ? threads : 1;
> + sockets = maxcpus / (cores * threads);
> + sockets = sockets > 0 ? sockets : 1;
> } else if (cores == 0) {
> threads = threads > 0 ? threads : 1;
> - cores = cpus / (sockets * threads);
> + cores = maxcpus / (sockets * threads);
> cores = cores > 0 ? cores : 1;
> } else if (threads == 0) {
> - threads = cpus / (cores * sockets);
> + threads = maxcpus / (sockets * cores);
> threads = threads > 0 ? threads : 1;
> - } else if (sockets * cores * threads < cpus) {
> + }
> +
> + if (sockets * cores * threads < cpus) {
> error_setg(errp, "cpu topology: "
> - "sockets (%u) * cores (%u) * threads (%u) < "
> - "smp_cpus (%u)",
> + "sockets (%u) * cores (%u) * threads (%u) "
> + "< smp_cpus (%u)",
> sockets, cores, threads, cpus);
> return;
> }
>
> - maxcpus = maxcpus > 0 ? maxcpus : cpus;
> -
> if (maxcpus < cpus) {
> error_setg(errp, "maxcpus must be equal to or greater than smp");
> return;
> @@ -795,9 +797,9 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
> }
>
> ms->smp.cpus = cpus;
> + ms->smp.sockets = sockets;
> ms->smp.cores = cores;
> ms->smp.threads = threads;
> - ms->smp.sockets = sockets;
> ms->smp.max_cpus = maxcpus;
> }
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 93d1f12a49..1812f33ab1 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -721,35 +721,36 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
>
> /* compute missing values, prefer sockets over cores over threads */
> dies = dies > 0 ? dies : 1;
> + maxcpus = maxcpus > 0 ? maxcpus : cpus;
>
> - if (cpus == 0 || sockets == 0) {
> + if (cpus == 0) {
> + sockets = sockets > 0 ? sockets : 1;
> cores = cores > 0 ? cores : 1;
> threads = threads > 0 ? threads : 1;
> - if (cpus == 0) {
> - sockets = sockets > 0 ? sockets : 1;
> - cpus = cores * threads * dies * sockets;
> - } else {
> - maxcpus = maxcpus > 0 ? maxcpus : cpus;
> - sockets = maxcpus / (dies * cores * threads);
> - sockets = sockets > 0 ? sockets : 1;
> - }
> + cpus = sockets * dies * cores * threads;
> + maxcpus = maxcpus > 0 ? maxcpus : cpus;
> + } else if (sockets == 0) {
> + cores = cores > 0 ? cores : 1;
> + threads = threads > 0 ? threads : 1;
> + sockets = maxcpus / (dies * cores * threads);
> + sockets = sockets > 0 ? sockets : 1;
> } else if (cores == 0) {
> threads = threads > 0 ? threads : 1;
> - cores = cpus / (sockets * dies * threads);
> + cores = maxcpus / (sockets * dies * threads);
> cores = cores > 0 ? cores : 1;
> } else if (threads == 0) {
> - threads = cpus / (cores * dies * sockets);
> + threads = maxcpus / (sockets * dies * cores);
> threads = threads > 0 ? threads : 1;
> - } else if (sockets * dies * cores * threads < cpus) {
> + }
> +
> + if (sockets * dies * cores * threads < cpus) {
> error_setg(errp, "cpu topology: "
> - "sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
> - "smp_cpus (%u)",
> + "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
> + "< smp_cpus (%u)",
> sockets, dies, cores, threads, cpus);
> return;
> }
>
> - maxcpus = maxcpus > 0 ? maxcpus : cpus;
> -
> if (maxcpus < cpus) {
> error_setg(errp, "maxcpus must be equal to or greater than smp");
> return;
> @@ -765,10 +766,10 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
> }
>
> ms->smp.cpus = cpus;
> - ms->smp.cores = cores;
> - ms->smp.threads = threads;
> ms->smp.sockets = sockets;
> ms->smp.dies = dies;
> + ms->smp.cores = cores;
> + ms->smp.threads = threads;
> ms->smp.max_cpus = maxcpus;
> }
>
next prev parent reply other threads:[~2021-07-13 7:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 10:07 [RFC PATCH 0/6] machine: smp parsing fixes and improvement Yanan Wang
2021-07-02 10:07 ` [RFC PATCH 1/6] machine: Set the value of maxcpus to match cpus if specified as zero Yanan Wang
2021-07-12 14:57 ` Andrew Jones
2021-07-12 15:27 ` Daniel P. Berrangé
2021-07-02 10:07 ` [RFC PATCH 2/6] machine: Perform zero-check for the computed value of sockets Yanan Wang
2021-07-12 15:00 ` Andrew Jones
2021-07-12 15:30 ` Daniel P. Berrangé
2021-07-13 6:56 ` wangyanan (Y)
2021-07-02 10:07 ` [RFC PATCH 3/6] pc/machine: Perform zero-check for the value of -smp dies Yanan Wang
2021-07-12 15:04 ` Andrew Jones
2021-07-12 15:05 ` Andrew Jones
2021-07-12 15:27 ` Andrew Jones
2021-07-13 6:46 ` wangyanan (Y)
2021-07-02 10:07 ` [RFC PATCH 4/6] machine: Uniformly use maxcpus to calculate the missing values Yanan Wang
2021-07-12 15:25 ` Andrew Jones
2021-07-13 7:25 ` wangyanan (Y)
2021-07-13 7:49 ` wangyanan (Y) [this message]
2021-07-02 10:07 ` [RFC PATCH 5/6] pc/machine: Disallow any configuration of dies for non-PC machines Yanan Wang
2021-07-02 10:18 ` Daniel P. Berrangé
2021-07-05 9:03 ` wangyanan (Y)
2021-07-02 10:07 ` [RFC PATCH 6/6] machine: Tweak the order of topology members in struct CpuTopology Yanan Wang
2021-07-12 15:29 ` Andrew Jones
2021-07-12 19:46 ` Pankaj Gupta
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