Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
qapi-schema.json | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/qapi-schema.json b/qapi-schema.json
index 82d6f12b53..0665a14dba 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -526,6 +526,10 @@
#
# Returns a list of information about each virtual CPU.
#
+# WARNING: This command incurs a performance penalty for latency
+# sensitive workloads and hence it's not recommended to
+# to be used in production. Use query-cpus-fast instead
+#
# Returns: a list of @CpuInfo for each virtual CPU
#
# Since: 0.14.0
--
2.14.3
On 02/07/2018 11:50 AM, Luiz Capitulino wrote: > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> > --- > qapi-schema.json | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/qapi-schema.json b/qapi-schema.json > index 82d6f12b53..0665a14dba 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -526,6 +526,10 @@ > # > # Returns a list of information about each virtual CPU. > # > +# WARNING: This command incurs a performance penalty for latency > +# sensitive workloads and hence it's not recommended to > +# to be used in production. Use query-cpus-fast instead > +# Ah, I asked for this on 1/2. You could squash these. I didn't review the code, just the interface, so if you squash them, you can add the weaker: Acked-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
On Wed, 7 Feb 2018 12:50:59 -0600 Eric Blake <eblake@redhat.com> wrote: > On 02/07/2018 11:50 AM, Luiz Capitulino wrote: > > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> > > --- > > qapi-schema.json | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/qapi-schema.json b/qapi-schema.json > > index 82d6f12b53..0665a14dba 100644 > > --- a/qapi-schema.json > > +++ b/qapi-schema.json > > @@ -526,6 +526,10 @@ > > # > > # Returns a list of information about each virtual CPU. > > # > > +# WARNING: This command incurs a performance penalty for latency > > +# sensitive workloads and hence it's not recommended to > > +# to be used in production. Use query-cpus-fast instead > > +# > > Ah, I asked for this on 1/2. You could squash these. > > I didn't review the code, just the interface, so if you squash them, you > can add the weaker: > > Acked-by: Eric Blake <eblake@redhat.com> OK, I'll wait for more review and do the changes you requested.
On Wed, Feb 07, 2018 at 12:50:14PM -0500, Luiz Capitulino wrote: > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> > --- > qapi-schema.json | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/qapi-schema.json b/qapi-schema.json > index 82d6f12b53..0665a14dba 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -526,6 +526,10 @@ > # > # Returns a list of information about each virtual CPU. > # > +# WARNING: This command incurs a performance penalty for latency > +# sensitive workloads and hence it's not recommended to > +# to be used in production. Use query-cpus-fast instead I suggest being more explicit about exactly what the problem is, so people understand implications if they choose to still use it. ie This command causes vCPU threads to exit to userspace, which causes an small interruption guest CPU execution. This will have a negative impact on realtime guests and other latency sensitive guest workloads. It is recommended to use query-cpus-fast instead of this command to avoid the vCPU interruption. 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 Thu, 8 Feb 2018 09:29:28 +0000 Daniel P. Berrangé <berrange@redhat.com> wrote: > On Wed, Feb 07, 2018 at 12:50:14PM -0500, Luiz Capitulino wrote: > > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> > > --- > > qapi-schema.json | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/qapi-schema.json b/qapi-schema.json > > index 82d6f12b53..0665a14dba 100644 > > --- a/qapi-schema.json > > +++ b/qapi-schema.json > > @@ -526,6 +526,10 @@ > > # > > # Returns a list of information about each virtual CPU. > > # > > +# WARNING: This command incurs a performance penalty for latency > > +# sensitive workloads and hence it's not recommended to > > +# to be used in production. Use query-cpus-fast instead > > I suggest being more explicit about exactly what the problem is, so people > understand implications if they choose to still use it. ie I'll add your text. > > This command causes vCPU threads to exit to userspace, which causes > an small interruption guest CPU execution. This will have a negative > impact on realtime guests and other latency sensitive guest workloads. > It is recommended to use query-cpus-fast instead of this command to > avoid the vCPU interruption. > > Regards, > Daniel
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