Compressed L1 cache

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ferrari
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Joined: Fri May 17, 2019 3:40 am

Compressed L1 cache

Post by ferrari » Sat Jul 13, 2019 8:57 pm

Would this be possible? I know zram on linux can compress ram contents to around 30% of original size at tremendous speed but I'm not sure if the data primocache caches can be compressed that much?

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support
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Re: Compressed L1 cache

Post by support » Mon Jul 15, 2019 3:39 am

Thank you for your suggestion. This is possible, however, the implementation is quite difficult within current program architecture. We consider this feature, but it will not come out in near feature.
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ferrari
Posts: 26
Joined: Fri May 17, 2019 3:40 am

Re: Compressed L1 cache

Post by ferrari » Thu Jul 18, 2019 7:39 pm

I just realized windows 10 has a new disk compression called CompactOS, which isn't ntfs compression it has new and updated compressioin schemes. I guess using compactOS to compress certain folders would mean the cached data would also be compressed, which means this feature basically already exists.
Testing out the new compression it can easily cope with the speed of a sata3 ssd, improving read speeds of certain files up to 4x.
https://github.com/ImminentFate/CompactGUI/releases

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Jaga
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Re: Compressed L1 cache

Post by Jaga » Fri Jul 19, 2019 1:52 am

ferrari wrote:
Thu Jul 18, 2019 7:39 pm
I just realized windows 10 has a new disk compression called CompactOS, which isn't ntfs compression it has new and updated compressioin schemes. I guess using compactOS to compress certain folders would mean the cached data would also be compressed, which means this feature basically already exists.
Testing out the new compression it can easily cope with the speed of a sata3 ssd, improving read speeds of certain files up to 4x.
https://github.com/ImminentFate/CompactGUI/releases
Haven't read up on this yet, thanks for pointing it out ferrari. Is it an on-the-fly compression, or during Windows idle? I'm wondering how it would affect IOPS on a fast NVMe drive, and whether or not it would be worth it for write speeds or as a read-only scheme.

ferrari
Posts: 26
Joined: Fri May 17, 2019 3:40 am

Re: Compressed L1 cache

Post by ferrari » Fri Jul 19, 2019 5:32 am

I did some basic speed testing with it on my ryzen 2600@stock. It can easily saturate 7200rpm and sata3 3 bandwidth with moderate cpu load, copying a compressed virtual disk from the 7200rpm to the ssd drive went between 300-400Mb/s(compared to the native 200Mb/s read speed of the hard disk). Decompressing a file on sata 3 ssd to itself also went full speed+decompression speed boost. With an nvme drive I think cpu load could start to get a little high though most I saw was 40%cpu load all cores and usually 10-20% load all cores(compression is multithreaded).

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Jaga
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Re: Compressed L1 cache

Post by Jaga » Sun Jul 21, 2019 11:34 pm

Sounds like a good feature, though probably not for the gaming segment. Probably best used with a high core environment where many sit idle most of the time. Still good to know, thanks!

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