Messages in this thread | | | Date | Mon, 29 Aug 2011 08:08:32 -0700 (PDT) | From | Dan Magenheimer <> | Subject | RE: cleancache can lead to serious performance degradation |
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> From: Nebojsa Trpkovic [mailto:trx.lists@gmail.com] > Subject: Re: cleancache can lead to serious performance degradation > > Thank you everybody for reviewing my report.
Thanks for reporting it! To paraphrase Clint Eastwood:
"A kernel developer's got to know his patchset's limitations".
(Clint said "A man's got to know his limitations" in Magnum Force, 1973.)
> I've noticed performance degradation during the real workload. I did not > run any special benchmarks to prove this problem. All my conclusions are > based on everyday usage case scenarios. > > I use multi-purpose (read: all-purpose) server with Intel Core 2 Duo > E6550, 8GB DDR2, 4 1Gbps NICs and 16 1.5TB 5.4k rpm hard drives in LAN > with ~50 workstations and WAN with couple of hundreds clients.
<snip>
OK, so the old CPU is mostly acting as a fancy router between 16 spindles and 4 fast NICs to transfer very large "packets" (sequential files). I can see how that kind of workload would not be kind to zcache, though a more modern multi-core (4-core i7?) might handle it better. And, as suggested earlier in this thread, a faster-but-less-space-efficient compression algorithm would be useful too, along with some policy that senses when
> Last but not least, thank you for developing such a great feature for > Linux kernel!
Thanks! Many people contributed (especially Nitin Gupta). I hope other users and workloads have better luck with it than you/yours does!
> Best Regards, > Nebojsa Trpkovic
Thanks, Dan
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