Re: Performance drop when updating > 500k pixels

2017-01-18 Thread Pierre Ossman
On 16/01/17 21:36, Adam Jackson wrote: On Fri, 2017-01-13 at 15:07 +0100, Pierre Ossman wrote: I'll answer myself here... This seems to be a CPU cache issue. Below this limit I see: 4,469,985 cache-misses:u#0.336 % of all cache refs 35,279,259,258 instru

Re: Performance drop when updating > 500k pixels

2017-01-16 Thread Adam Jackson
On Fri, 2017-01-13 at 15:07 +0100, Pierre Ossman wrote: > I'll answer myself here... > > This seems to be a CPU cache issue. Below this limit I see: > >  4,469,985  cache-misses:u#0.336 % of all cache > refs > 35,279,259,258  instructions:u#  

Re: Performance drop when updating > 500k pixels

2017-01-13 Thread Pierre Ossman
On 12/01/17 13:53, Pierre Ossman wrote: > > For small updates I see performance growing logarithmically, measured in > pixels/second. At around 500k pixels it starts leveling off at ~1.5 > Gpixels/second. After that the performance starts dropping linearly as > the update grows. I'll answer mysel