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vl.c: Add -smp, dies=* command line support and update doc
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For PC target, users could configure the number of dies per one package
via command line with this patch, such as "-smp dies=2,cores=4".

The parsing rules of new cpu-topology model obey the same restrictions/logic
as the legacy socket/core/thread model especially on missing values computing.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20190620054525.37188-4-like.xu@linux.intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
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@ehabkost
Like Xu authored and ehabkost committed Jul 5, 2019
1 parent 6f47956 commit 1b45842
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Showing 3 changed files with 29 additions and 21 deletions.
30 changes: 17 additions & 13 deletions hw/i386/pc.c
View file
Expand Up @@ -1540,9 +1540,12 @@ static void pc_new_cpu(PCMachineState *pcms, int64_t apic_id, Error **errp)
*/
void pc_smp_parse(MachineState *ms, QemuOpts *opts)
{
PCMachineState *pcms = PC_MACHINE(ms);

if (opts) {
unsigned cpus = qemu_opt_get_number(opts, "cpus", 0);
unsigned sockets = qemu_opt_get_number(opts, "sockets", 0);
unsigned dies = qemu_opt_get_number(opts, "dies", 1);
unsigned cores = qemu_opt_get_number(opts, "cores", 0);
unsigned threads = qemu_opt_get_number(opts, "threads", 0);

Expand All @@ -1552,24 +1555,24 @@ void pc_smp_parse(MachineState *ms, QemuOpts *opts)
threads = threads > 0 ? threads : 1;
if (cpus == 0) {
sockets = sockets > 0 ? sockets : 1;
cpus = cores * threads * sockets;
cpus = cores * threads * dies * sockets;
} else {
ms->smp.max_cpus =
qemu_opt_get_number(opts, "maxcpus", cpus);
sockets = ms->smp.max_cpus / (cores * threads);
sockets = ms->smp.max_cpus / (cores * threads * dies);
}
} else if (cores == 0) {
threads = threads > 0 ? threads : 1;
cores = cpus / (sockets * threads);
cores = cpus / (sockets * dies * threads);
cores = cores > 0 ? cores : 1;
} else if (threads == 0) {
threads = cpus / (cores * sockets);
threads = cpus / (cores * dies * sockets);
threads = threads > 0 ? threads : 1;
} else if (sockets * cores * threads < cpus) {
} else if (sockets * dies * cores * threads < cpus) {
error_report("cpu topology: "
"sockets (%u) * cores (%u) * threads (%u) < "
"sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
"smp_cpus (%u)",
sockets, cores, threads, cpus);
sockets, dies, cores, threads, cpus);
exit(1);
}

Expand All @@ -1581,26 +1584,27 @@ void pc_smp_parse(MachineState *ms, QemuOpts *opts)
exit(1);
}

if (sockets * cores * threads > ms->smp.max_cpus) {
if (sockets * dies * cores * threads > ms->smp.max_cpus) {
error_report("cpu topology: "
"sockets (%u) * cores (%u) * threads (%u) > "
"sockets (%u) * dies (%u) * cores (%u) * threads (%u) > "
"maxcpus (%u)",
sockets, cores, threads,
sockets, dies, cores, threads,
ms->smp.max_cpus);
exit(1);
}

if (sockets * cores * threads != ms->smp.max_cpus) {
if (sockets * dies * cores * threads != ms->smp.max_cpus) {
warn_report("Invalid CPU topology deprecated: "
"sockets (%u) * cores (%u) * threads (%u) "
"sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
"!= maxcpus (%u)",
sockets, cores, threads,
sockets, dies, cores, threads,
ms->smp.max_cpus);
}

ms->smp.cpus = cpus;
ms->smp.cores = cores;
ms->smp.threads = threads;
pcms->smp_dies = dies;
}

if (ms->smp.cpus > 1) {
Expand Down
17 changes: 9 additions & 8 deletions qemu-options.hx
View file
Expand Up @@ -138,25 +138,26 @@ no incompatible TCG features have been enabled (e.g. icount/replay).
ETEXI
DEF("smp", HAS_ARG, QEMU_OPTION_smp,
"-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]\n"
"-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
" set the number of CPUs to 'n' [default=1]\n"
" maxcpus= maximum number of total cpus, including\n"
" offline CPUs for hotplug, etc\n"
" cores= number of CPU cores on one socket\n"
" cores= number of CPU cores on one socket (for PC, it's on one die)\n"
" threads= number of threads on one CPU core\n"
" dies= number of CPU dies on one socket (for PC only)\n"
" sockets= number of discrete sockets in the system\n",
QEMU_ARCH_ALL)
STEXI
@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,dies=dies][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
@findex -smp
Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
to 4.
For the PC target, the number of @var{cores} per socket, the number
of @var{threads} per cores and the total number of @var{sockets} can be
specified. Missing values will be computed. If any on the three values is
given, the total number of CPUs @var{n} can be omitted. @var{maxcpus}
specifies the maximum number of hotpluggable CPUs.
For the PC target, the number of @var{cores} per die, the number of @var{threads}
per cores, the number of @var{dies} per packages and the total number of
@var{sockets} can be specified. Missing values will be computed.
If any on the three values is given, the total number of CPUs @var{n} can be omitted.
@var{maxcpus} specifies the maximum number of hotpluggable CPUs.
ETEXI

DEF("numa", HAS_ARG, QEMU_OPTION_numa,
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3 changes: 3 additions & 0 deletions vl.c
View file
Expand Up @@ -1231,6 +1231,9 @@ static QemuOptsList qemu_smp_opts = {
}, {
.name = "sockets",
.type = QEMU_OPT_NUMBER,
}, {
.name = "dies",
.type = QEMU_OPT_NUMBER,
}, {
.name = "cores",
.type = QEMU_OPT_NUMBER,
Expand Down

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