Patches concerning the speed of mouse-movement over the profile.

[Lubomir I. Ivanov]

On 15 January 2015 at 02:56, Tomaz Canabrava <tcanabrava at kde.org> wrote:
> Lubomir,
>
> I'v removed almost every allocation that I could find. can you try this 8
> patches and tell me if anything worked to reduce the cpu usage?
>
>
> We can still do some stuff to not remove the animations  ( yup, I like them
> )
> like using a square instead of a rounded - rect notification panel.
>
>

unfortunately the patches did not improve the performance much for me
- it's still above 20%.
but i suggest you skip any more fixes for this ATM, because we have no
user complains.

the allocations boosted it, but setText(), setPixmap() and the little
graph drawing still require high CPU usage.

it started to smell to me as a FPU denormal issue, so i tested that
because i've noticed the GCC uses FPU instructions for this particular
part and the control word flag was unset, but it ain't the cause,
unless Qt updates the FPU between calls.

-O3 doesn't helps which means that calls to another library are heavy (e.g. Qt).

i've also tried using S&H on refresh() to reduce the amounts of calls
on power of two intervals and that is the only thing that helps, but
reduces the smoothness of the tooltip itself and isn't pretty; a
factor of 4 is tolerable but still caps at more than 16% CPU usage.

perhaps there are other tricks to try, but i don't have the time.

overall i'm very surprised that such as simple UI element is so slow
in Qt. i've written *much more* complicated UI in other languages and
frameworks and it was blazing fast compared to this.

but like i said, leave it be for now IMHO.

lubomir
--