A couple of interesting performance anomalies

Hi,

I’ve noticed two performance anomalies with SIRIL:

  1. On my 24-core/32-thread Intel i-9 14th gen 16-Gig RAM, 4TB NVME SSD, Windows 11 system, even if I set SIRIL to only use a much smaller number of threads, say 12 threads, it’ll still use 50-100% of the CPU. If I cut it all the way down to 4 threads, it’ll finally drop back to 30-40% of the CPU. (No other software is running other than Windows, no virus programs, etc… and this is very repeatable. When SIRIL stops, CPU drops to <5%.

Is there a reason why it doesn’t seem to be very proportional to how many CPUs and Threads I have. I would expect if I cut it to 12, I would see <50% of the CPU being utilized.

  1. When I stack with SIRIL, generally I can get OK performance running other tasks (ex: Browsing or doing a bit of editing in Affinity). However, I shoot short exposures and often stack my subs into 10-minute sub-stacks and then stack these. So these substacks are already debayered, calibrated and are 32-bit/pixel RICE FITS compressed stacks. if I stack a group of about 172 of these compressed 32-bit/pixel sub-stacks with SIRIL, even with only 12 threads, my system becomes pretty unresponsive. I can’t even type into Explorer, I get 1 character every 2 seconds.

I haven’t fully explored this, but It seems there is something about this data type: 32-bit/pixel RICE FITS files that really impacts SIRIL. I did note that 100% of the CPU is used and of my 16-GIgs of RAM, it’s all used by SIRIL and the commit charges go up to 28 Gigs (not sure if that’s important). Just a note.

12 compute threads need to be supplied with data. that means windows has to do more work as well. also managing threads and supplying data to it, requires work.

last but not least … you have have a little core-big core cpu. if the 12 threads are all on your p-cores then that is a much bigger part of the maximum power of the CPU. the e-cores represent a much smaller part.

hth

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for question 1 I’m unsure how that works, but with an SMP CPU that would not be normal

for question 2, dealing with 32 bit and 3 channel images is much heavier in I/O than working with the original images, windows doesn’t like that much and tends to freeze. It also happens when there is not enough memory available, maybe you should reduce the quantity of memory dedicated to siril in the preferences, in ratio of available (default is 90%)

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