Yet another "optimal settings for my setup" thread

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Drake713
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Yet another "optimal settings for my setup" thread

Post by Drake713 »

Some background; I was using Intel Optane on my PC for the last ~5years and kinda loved it, then I upgraded hardware and found out that Optane (the software at least) could not run on chipsets past gen 10 or maybe 11 and here I am with a gen 13 CPU now. So I looked into the options; Fuzedrive, etc and found they are discontinued as well. Which brings me to Primocache - it's not exactly the same (tiered solution vs caching solution) but the end result is similar; speed up an HDD.

Ok, so I tried it out with the "Accelerate Reads and Writes" strategy on a system that is 32gb of Ram with a 32gb (new) Optane SSD accelerating a 9TB HDD. I do still have my old 32gb Optane SSD too but it looks to only have 16% life left so I'm just storing the system pagefile on it atm
I initially just accepted the default recommended value for the L1cache of ~13gb with deferred writes enabled at the default 10s and the default 256kb block size, only settings I think I tweaked were - set the caching strategy to "averaging" and enabled freewritten and flushsleep.
I started getting weirdness cropping up tho; The Callisto Protocol started getting this error message:
https://steamcommunity.com/app/1544020/ ... 405610619/
An error usually associated with raytracing, but raytracing was already disabled for both shadows and reflections... But TCP is new and still buggy so maybe it was just the game and not Primocache, right? So I booted up Kingdom Come Deliverance which is older and had been perfectly stable before I started using Primocache and what do you know it was crashing non-stop too. Most of the time it just crashed flat out, but once it did popup a small error message saying something about being unable to allocate memory, but I don't have a screenshot of that one. Anyway I disabled L1caching completely and what do you know the crashes in BOTH games stopped.

I've communicated these details to Tech Support already via email, but what I would like from this forum is some advice on what my settings *should* be.
I'm testing out read-only for both L1 and L2 and set the cache size for L1 to 6gb with NO write caching at all let alone differed writes atm.
Should I tweak the block size? Risk increasing that L1 size? My guess is maybe the crashes were coming from the differed writes but idk for sure and I don't like programs crashing >.>

btw why can't I get more than 27gb out of that 32gb drive?
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tverweij
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Re: Yet another "optimal settings for my setup" thread

Post by tverweij »

You might want to do a test with CrystalDiskMark with all availabel caching block sizes.
I see that you cache 256k blocks (I did 4k in the past) - but when I started measuring on my systems, I found that the optimal blocksize was 32k in my case. Smaller blocks made everything slower, bigger blocks were also slower.
(see topic: viewtopic.php?t=5591 for the measurements in my system)
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Drake713
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Re: Yet another "optimal settings for my setup" thread

Post by Drake713 »

tverweij wrote: Mon Jan 09, 2023 12:23 pm You might want to do a test with CrystalDiskMark with all availabel caching block sizes.
I see that you cache 256k blocks (I did 4k in the past) - but when I started measuring on my systems, I found that the optimal blocksize was 32k in my case. Smaller blocks made everything slower, bigger blocks were also slower.
(see topic: viewtopic.php?t=5591 for the measurements in my system)
Hmmm 32k or 64k seems like the sweet spots... I'll have to test mine and see what the results are... thanks mate!
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Re: Yet another "optimal settings for my setup" thread

Post by Support »

Small block size will result in large cache overhead, especially when the capacity of target drives is huge. I estimate the cache overhead will be about 650MB when block size is 64KB and overhead will be about 1.3GB when the block size is 32KB. I think you should be using at least a 64kb cache block size in order not to waste too much RAM in cache overhead.
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