[PATCH v2 13/15] conf: Expose QEMU's main loop object

[Peter Krempa]

On Tue, Jun 07, 2022 at 14:52:57 +0200, Michal Privoznik wrote:
> As of v7.0.0-877-g70ac26b9e5 QEMU exposes its main event loop as
> an QMP object. In the very next commit (v7.0.0-878-g71ad4713cc)
> it was extended for thread-pool-min and thread-pool-max
> attributes. Expose them under new <mainloop/> element.

Please fix the summary and commit message. Make sure to mention the name
of the element.

> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  docs/formatdomain.rst                         |  9 +++
>  src/conf/domain_conf.c                        | 63 +++++++++++++++++++
>  src/conf/domain_conf.h                        |  8 +++
>  src/conf/schemas/domaincommon.rng             | 15 +++++
>  src/conf/virconftypes.h                       |  2 +
>  .../iothreads-ids-pool-sizes.xml              |  1 +
>  6 files changed, 98 insertions(+)
> 
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index 2aa39b2f63..22eb540ba3 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -677,6 +677,7 @@ host/guest with many LUNs. :since:`Since 1.2.8 (QEMU only)`
>         <iothread id="6"/>
>         <iothread id="8" thread_pool_min="2" thread_pool_max="32"/>
>       </iothreadids>
> +     <defaultiothread thread_pool_min="8" thread_pool_max="16">
>       ...
>     </domain>
>  
> @@ -699,6 +700,14 @@ host/guest with many LUNs. :since:`Since 1.2.8 (QEMU only)`
>     The element has two optional attributes ``thread_pool_min`` and
>     ``hread_pool_max`` which allow setting lower and upper boundary for number
>     of worker threads for given IOThread. :since:`Since 8.5.0`
> +``defaultiothread``
> +   The element then can have ``thread_pool_min`` and/or ``thread_pool_max``
> +   attributes, which control the lower and upper boundary for number of worker
> +   threads for the emulator. Emulator might be multithreaded and spawn so
> +   called worker threads on demand. In general neither of these attributes
> +   should be set (leaving the emulator use its own default values), unless the
> +   emulator runs in a real time workload and thus can't afford unpredictability
> +   of time it takes to spawn new worker threads. :since:`Since 8.5.0`

This description doesn't seem to capture what actually the
'defaultiothread' element represents. It starts right away by describing
it's arguments. Users might be confused.

I don't have a specific suggestion though.

The code looks good:

Reviewed-by: Peter Krempa <pkrempa at redhat.com>