Re: [libvirt] [PATCHv2 08/11] qemu: bulk stats: implement VCPU group
----- Original Message -----
From: "Eric Blake" <eblake(a)redhat.com>
To: "Francesco Romani" <fromani(a)redhat.com>, libvir-list(a)redhat.com
Sent: Wednesday, September 3, 2014 1:00:53 AM
Subject: Re: [libvirt] [PATCHv2 08/11] qemu: bulk stats: implement VCPU group
On 09/02/2014 06:31 AM, Francesco Romani wrote:
> This patch implements the VIR_DOMAIN_STATS_VCPU
> group of statistics.
>
> Signed-off-by: Francesco Romani <fromani(a)redhat.com>
> ---
> include/libvirt/libvirt.h.in | 1 +
> src/libvirt.c | 8 +++++
> src/qemu/qemu_driver.c | 72
> ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 81 insertions(+)
>
> *
> + * VIR_DOMAIN_STATS_VCPU: Return virtual CPU statistics.
> + * The typed parameter keys are in this format:
> + * "vcpu.current" - current number of online virtual CPUs
> + * "vcpu.maximum" - maximum number of online virtual CPUs
> + * "vcpu.<num>.state" - state of the virtual CPU <num>
Is this an int mapping to some particular enum?
Yep: virVcpuState. Will document this.
> + * "vcpu.<num>.time" - virtual cpu time spent
by virtual CPU <num>
> + * "vcpu.<num>.cpu" - physical CPU pinned to virtual CPU
<num>
Missing types.
Should there be a parameter vcpu.count that says how many vcpu.<num>
entries to expect? Or is that vcpu.current? Or do we have a situation
where if cpus 0 and 2 are online but 1 and 3 are offline, then we have
vcpu.0.x and vcpu2.x but not vcpu1.x?
Yes, the latter, due to VCPU hot(un)plugging
A bit more documentation will help the user deciding which
"array"
entries to expect, and whether the "array" will be sparse if cpus are
offline.
Will document that the array will be up to "vcpu.maximum" items, could
be sparse and the actual size will be of "vcpu.current" items.
> +{
> + size_t i;
> + int ret = -1;
> + char param_name[NAME_MAX];
NAME_MAX (typically 256) is huge, compared to
VIR_TYPED_PARAM_FIELD_LENGTH (80).
Will switch to VIR_TYPED_PARAM_FIELD_LENGTH here and everywhere I used
NAME_MAX.
Thanks,
--
Francesco Romani
RedHat Engineering Virtualization R & D
Phone: 8261328
IRC: fromani