[libvirt] [PATCH] qemu: Limit refresh of CPU halted state to s390
Refreshing the halted state can cause VM performance issues. Since s390 is currently the only architecture with a known interest in the halted state, we're avoiding to call QEMU on other platforms. Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- src/qemu/qemu_domain.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index df433c2..d2c833f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -8634,6 +8634,10 @@ qemuDomainRefreshVcpuHalted(virQEMUDriverPtr driver, if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) return 0; + /* Only supported on s390(x) */ + if (!ARCH_IS_S390(vm->def->os.arch)) + return 0; + if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0) return -1; -- 1.9.1
On Tue, Feb 06, 2018 at 11:18:56 +0100, Viktor Mihajlovski wrote:
Refreshing the halted state can cause VM performance issues. Since s390 is currently the only architecture with a known interest in the halted state, we're avoiding to call QEMU on other platforms.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- src/qemu/qemu_domain.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index df433c2..d2c833f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -8634,6 +8634,10 @@ qemuDomainRefreshVcpuHalted(virQEMUDriverPtr driver, if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) return 0;
+ /* Only supported on s390(x) */ + if (!ARCH_IS_S390(vm->def->os.arch)) + return 0;
I think we also should remove the 'halted' field from the stats output if the information was not gathered at all, since it would falsely reply that the cpu is not halted all the time.
On Tue, Feb 06, 2018 at 11:55:07 +0100, Peter Krempa wrote:
On Tue, Feb 06, 2018 at 11:18:56 +0100, Viktor Mihajlovski wrote:
Refreshing the halted state can cause VM performance issues. Since s390 is currently the only architecture with a known interest in the halted state, we're avoiding to call QEMU on other platforms.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- src/qemu/qemu_domain.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index df433c2..d2c833f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -8634,6 +8634,10 @@ qemuDomainRefreshVcpuHalted(virQEMUDriverPtr driver, if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) return 0;
+ /* Only supported on s390(x) */
This would also benefit from a more thorough comment.
+ if (!ARCH_IS_S390(vm->def->os.arch)) + return 0;
I think we also should remove the 'halted' field from the stats output if the information was not gathered at all, since it would falsely reply that the cpu is not halted all the time.
Also to do so you'll probably need to convert the 'halted' bool to a tristate, so that the logic determining whether the field should be used or not is not present in the stats code but it's in the refresh code as you've added it.
On Tue, Feb 06, 2018 at 12:00:31PM +0100, Peter Krempa wrote:
On Tue, Feb 06, 2018 at 11:55:07 +0100, Peter Krempa wrote:
On Tue, Feb 06, 2018 at 11:18:56 +0100, Viktor Mihajlovski wrote:
Refreshing the halted state can cause VM performance issues. Since s390 is currently the only architecture with a known interest in the halted state, we're avoiding to call QEMU on other platforms.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- src/qemu/qemu_domain.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index df433c2..d2c833f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -8634,6 +8634,10 @@ qemuDomainRefreshVcpuHalted(virQEMUDriverPtr driver, if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) return 0;
+ /* Only supported on s390(x) */
This would also benefit from a more thorough comment.
+ if (!ARCH_IS_S390(vm->def->os.arch)) + return 0;
I think we also should remove the 'halted' field from the stats output if the information was not gathered at all, since it would falsely reply that the cpu is not halted all the time.
Also to do so you'll probably need to convert the 'halted' bool to a tristate, so that the logic determining whether the field should be used or not is not present in the stats code but it's in the refresh code as you've added it.
Or the lazy way out is to just add ARCH_IS_S390() check in the stats method too Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On Tue, Feb 06, 2018 at 11:05:06 +0000, Daniel Berrange wrote:
On Tue, Feb 06, 2018 at 12:00:31PM +0100, Peter Krempa wrote:
On Tue, Feb 06, 2018 at 11:55:07 +0100, Peter Krempa wrote:
On Tue, Feb 06, 2018 at 11:18:56 +0100, Viktor Mihajlovski wrote:
Refreshing the halted state can cause VM performance issues. Since s390 is currently the only architecture with a known interest in the halted state, we're avoiding to call QEMU on other platforms.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- src/qemu/qemu_domain.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index df433c2..d2c833f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -8634,6 +8634,10 @@ qemuDomainRefreshVcpuHalted(virQEMUDriverPtr driver, if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) return 0;
+ /* Only supported on s390(x) */
This would also benefit from a more thorough comment.
+ if (!ARCH_IS_S390(vm->def->os.arch)) + return 0;
I think we also should remove the 'halted' field from the stats output if the information was not gathered at all, since it would falsely reply that the cpu is not halted all the time.
Also to do so you'll probably need to convert the 'halted' bool to a tristate, so that the logic determining whether the field should be used or not is not present in the stats code but it's in the refresh code as you've added it.
Or the lazy way out is to just add ARCH_IS_S390() check in the stats method too
No. That's exactly why I've sent this second mail. I don't want to litter this stuff into the stats method. The stats method should not care what weirdness is necessary for a given arch.
participants (3)
-
Daniel P. Berrangé -
Peter Krempa -
Viktor Mihajlovski