Re: [PATCH] xen/console: pre-compute domain prefix for printouts

[Denis Mukhin <dmkhn@xxxxxxxxx>]

On Thursday, February 13th, 2025 at 3:28 PM, Andrew Cooper 
<andrew.cooper3@xxxxxxxxxx> wrote:

>
>
> On 13/02/2025 10:35 pm, dmkhn@xxxxxxxxx wrote:
>
> > Every guest_printk() call computes "(d%d) " prefix on every call.
> > Move prefix generation to the domain creation time.
> >
> > Signed-off-by: Denis Mukhin dmukhin@xxxxxxxx
>
>
> I'm on the fence here.
>
> Part of that is speaking as someone who has had to shrink struct domain
> several times to keep it fitting within 1 page.
>
> But as to calculating it every time, does that matter? In production
> environments, we get a handful of print lines per domain across their
> lifetime. Is the saving really worth it?

Our setup should support domain restarts with heavy logging enabled.
While restarts are not expected to happen very often, when restart happens
the system shall boot to operational state pretty quickly.

Also, I was planning to use this code to address the feedback from:
  
https://lore.kernel.org/xen-devel/cKowJ0lJhKcoHoaPgGOX4xdDu6PCcg7MVnhS_y5L4mVGJfNlG-xXJdSGXJkIys5OqdCeSdiYtNQmI4znkjXLaqtqHefgvM33MbvMX700nk0=@proton.me/

The code (unposted) is here:
  
https://gitlab.com/xen-project/people/dmukhin/xen/-/commit/bf72477b77a09853c69319afed5280bff4eabb1d#f29178524efff3dcdb2342a5a4e5affb5fe99fd1

>
> ~Andrew