Messages in this thread | | | Date | Wed, 24 Sep 2008 10:56:57 -0300 | From | "Luiz Fernando N. Capitulino" <> | Subject | Re: [PATCH] VM: Implements the swap-out page-clustering technique |
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Em Thu, 04 Sep 2008 15:34:30 +0330 "Hamid R. Jahanjou" <hamid.jahanjou@gmail.com> escreveu:
| From: Hamid R. Jahanjou | | Implements the idea of swap-out page clustering from *BSD for | Linux. Each time a candidate page is to be swapped out, | virtually-nearby pages are scanned to find eligible pages to be | swapped out too as a cluster. This technique increases the likelihood of | bringing in related data on a page fault and decreases swap space | fragmentation in the long run. Currently, Linux searches only | physically-nearby pages which is not optimal since, over time, physically- | adjacent pages may become unrelated. | | The code can be statically tuned. No benchmarks. I'm not sure whether | the added complexity is acceptable.
Sorry for this (very) late response, but I ran some very simple tests this week and thought you might be interested in the results.
The test machine has 512MB of RAM. For the tests I booted with 64MB and setup a 512MB swap file.
For the first test I let an allyesconfig kernel building for several hours with six jobs (make -j6). I did not have any problems, so considering that your code was used I think it is stable enough.
In the second test I have built an allnoconfig kernel with and without your patches, still with six jobs. Results:
2.6.27-rc7-vanilla 44:12 minutes 2.6.27-rc7-pgc 52:09 minutes
(pgc means page-clustering patches).
For both builds I did not change any swap paramenter and I could observe that about 80MB of swap were used most of the time.
But please, note that these tests were quite far from being 'scientific' eg. I should have built the kernel more times and should have tried other setups...
I will wait for the next version of the patches to run more serious tests.
-- Luiz Fernando N. Capitulino
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