Hi Drew,
On 2021/7/12 23:25, Andrew Jones wrote:
On Fri, Jul 02, 2021 at 06:07:37PM +0800, 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.
Signed-off-by: Yanan Wang <wangyana...@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;
As stated in the other patch, this rounding up of a fractional sockets
shouldn't be here. maxcpus or (cpus==maxcpus) should always be selected by
the user to be a product of whole number sockets, cores, threads.
I also default sockets to 1 if computed as zero because we are doing
this for cores/threads and I did't see the difference between them.
Anyway, now that we are using maxcpus for all calculations, so we can
either get rid of all the rounding-ups for sockets/cores/threads or just
keep them all.
With the rouding-up, we get:
-smp cpus=12,cores=16,maxcpus=12 --> -smp
cpus=12,sockets=0,cores=16,threads=1,maxcpus=12 --> error_report
without the rounding-up we get:
-smp cpus=12,cores=16,maxcpus=12 --> -smp
cpus=12,sockets=1,cores=16,threads=1,maxcpus=12 --> error_report
We will both get an error report as expected, but I can get rid of the
rounding if it's preferred.
} else if (cores == 0) {
threads = threads > 0 ? threads : 1;
- cores = cpus / (sockets * threads);
+ cores = maxcpus / (sockets * threads);
cores = cores > 0 ? cores : 1;
Now that we're using maxcpus for the calculation, then no rounding for
cores either...
} else if (threads == 0) {
- threads = cpus / (cores * sockets);
+ threads = maxcpus / (sockets * cores);
threads = threads > 0 ? threads : 1;
...or threads.
- } 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)",
Why make this change?
No need actually, will change it back. :)
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;
}
Same comments as for the general function.
Thanks,
drew
- 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;
}
--
2.19.1
Thanks,
Yanan
.
.
