Messages in this thread | | | Date | Thu, 18 Jul 2013 20:43:40 +0800 | From | Bob Liu <> | Subject | Re: zswap: How to determine whether it is compressing swap pages? |
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Hi Martin,
On 07/18/2013 03:38 AM, Martin Steigerwald wrote: > Am Mittwoch, 17. Juli 2013, 09:38:34 schrieb Seth Jennings: >> On Wed, Jul 17, 2013 at 01:41:44PM +0200, Martin Steigerwald wrote: >>> Is there any way to run zcache concurrently with zswap? I.e. use zcache only >>> for read caches for filesystem and zswap for swap? >> >> No, at least not with zcache's frontswap features enabled. frontswap is a very >> simple API that allows only one "backend" to register with it at a time. So >> that means _either_ zswap or zcache. >> >> The only way they can be used in a meaningful way together is to use the >> "nofrontswap" zcache option in the kernel boot parameters to prevent >> zcache overriding zswap's frontswap registration. >> >> But the general answer is no, they shouldn't be used together. >> >> >>> >>> What is better suited for swap? zswap or zcache? >> >> zswap targets the specific case of caching swapped out pages in a compressed >> cache and this is much simpler than zcache. zswap is also in mainline as of >> 3.11-rc1. > > Thanks. > > Okay, then I will test zswap for now. I have a nice use case for it: Playing
Could you make some test by kernel compiling? Something like kernbench. During my testing, I found that the swap ins/outs operations reduced but the kernel compile time didn't reduce accordingly.
-- Regards, -Bob
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