Re: [PATCH 0/7] misc: Reduce QEMUTimer pressure by using lower precision when possible

[Paolo Bonzini]

On 18/06/20 14:26, Philippe Mathieu-Daudé wrote:
>> This is in principle a very good idea; however, util/qemu-timer.c does
>> not use the scale to coalesce low-precision timers with nearby
>> high-precision ones.
> IOW this doesn't reduce the pressure, but simply makes the code easier?

Easier, or harder depending on the point of view.  The reason why scale
exists is just because QEMU_CLOCK_REALTIME used to be millisecond based;
having to scale based on the clock was really ugly code, and furthermore
the scale provides an easy way to switch timers from one clock to
another without having to modify every deadline computation.

One might argue that the scale adds to QEMU's cognitive weight for
little benefit.  You might counter-argue that having to scale up to
nanoseconds every time is a pain in the ass, and I am not sure which
side I actually agree with.

> Only the cover mentions 'pressure', so maybe the patches can still be
> reviewed/queued in their current state?

Yes, of course.

Paolo