Originally posted by milkylainen
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Intel Optimization Around Batched TLB Flushing For Folios Looks Great
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Originally posted by sinepgib View Post
The rest would be long to explain and I'm likely to get it wrong, but this part is simple: look up huge pages, x86 systems support them at the hardware level.
edit 20*8 is actually 160 byte that would mean 20 pointers vs 1 thats a significant reduction but how do you split the 20 pages after that ????
edit2 if i read my own post i c that from a 4k page to 2m page its probably better to use 8 byte for 2m then to use 8 byte for 4k you save 4088 bytes allmost a hole page
Last edited by erniv2; 20 January 2023, 10:15 PM.
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Originally posted by sinepgib View PostSounds like a sensible concern.
AFAIK there's no downside to folios. Batching OTOH is a compromise, but one does not imply the other.
Afaiu, we're talking physically continuous pages?
Maybe people already did higher order allocations, so this was just an unification in handling?
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Originally posted by erniv2 View PostI always thought that most things get stored in 4k chunks cause thats the native page size well atlast for x86 systems.
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Originally posted by xnor View Post
First result on ddg for "linux folio": https://lwn.net/Articles/849538/
And at the CPU cycle level how much is saved/lost convertig a native 4k page to a set of folio pages ? I always thought that most things get stored in 4k chunks cause thats the native page size well atlast for x86 systems.
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Originally posted by willmore View PostCan someone summarize what a folio is in this situation? Google only returns this article and the patch refered to in it. Neither tells me what it is. Thank you.
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Can someone summarize what a folio is in this situation? Google only returns this article and the patch refered to in it. Neither tells me what it is. Thank you.
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Originally posted by milkylainen View PostThroughput is one thing. Batching is a classic for increasing throughput.
But usually, you sacrifice latency or have latency spikes.
Is this something that RT folks will hate?
Originally posted by milkylainen View PostAlso (clueless warning), folios seem to be always enabled?
Ie, it's not something you can opt out from?
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Throughput is one thing. Batching is a classic for increasing throughput.
But usually, you sacrifice latency or have latency spikes.
Is this something that RT folks will hate?
Also (clueless warning), folios seem to be always enabled?
Ie, it's not something you can opt out from?
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Intel Optimization Around Batched TLB Flushing For Folios Looks Great
Phoronix: Intel Optimization Around Batched TLB Flushing For Folios Looks Great
A patch worked on by an Intel engineer for batched TLB flushing for page migration with folios is showing some promising results and currently working its way to the mainline kernel...
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