Messages in this thread |  | | | Subject | Re: [PATCH] Radix-tree pagecache for 2.5 | | From | Momchil Velikov <> | | Date | 30 Jan 2002 01:02:11 +0200 |
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>>>>> "Linus" == Linus Torvalds <torvalds@transmeta.com> writes:
Linus> In article <20020129165444.A26626@caldera.de>, Linus> Christoph Hellwig <hch@caldera.de> wrote: >> I've ported my hacked up version of Momchil Velikov's radix tree >> radix tree pagecache to 2.5.3-pre{5,6}. >> >> The changes over the 2.4.17 version are: >> >> o use mempool to avoid OOM situation involving radix nodes. >> o remove add_to_page_cache_locked, it was unused in the 2.4.17 patch. >> o unify add_to_page and add_to_page_unique >> >> It gives nice scalability improvements on big machines and drops the >> memory usage on small ones (if you consider my 64MB Athlon small :)).
Linus> Can you post the numbers on scalability (I can see the locking Linus> improvement, but if you have numbers I'd be even happier) and any Linus> benchmarks you have?
Well, these are dbench numbers from December, it's 2.4.17. Unfortunately, it appears OSDL have trouble with 2.5 currently ...
FWIW, box is 8-way PIII Xeon, 700MHz, 1MB cache, 8G RAM
rat-7 is with 128-way radix tree branch factor, rat-4 is with 16-way.
#Clients 2.4.17 2.4.17-rat-7 2.4.17-rat-4 --------------------------------------------------------- 1 81.81 82.70 79.49 2 131.77 133.15 116.32 3 179.74 188.04 184.80 4 221.60 228.70 223.97 5 249.86 252.89 258.77 6 260.56 277.70 265.20 7 285.82 287.47 281.27 8 263.61 258.81 256.29 9 271.06 268.29 261.04 10 261.23 265.82 259.34 11 256.82 260.38 258.35 12 255.55 255.68 252.78 13 252.70 254.02 249.42 14 251.41 253.93 252.21 15 255.27 257.13 262.21 16 156.81 146.69 180.77 17 113.00 103.32 101.14 18 81.06 78.98 86.77 19 76.24 40.09 39.89 20 17.51 17.64 17.53 The results are similar on 4-way OSDL boxen and on the 12- and 16-way PPC64 runs by Anton Blanchard:
# clients [1 - ncpu] - linear increase in the throughput, small improvement over the stock kernel, I guess we quickly hit other locks [ncpu - 2 * ncpu] - flat [2 * ncpu, +infty) - drops down do zero
Linus> The only real complaint I have is that I'd rather see "radix_root" than Linus> "rat_root". Maybe it is just me, but the latter makes me wonder about Linus> the sex-lives of small furry mammals. Which is not what I really want to Linus> be thinking about.
Done. rat_* -> radix_tree_*
Linus> It looks straigthforward enough, so if you feel it is stable (and Linus> cleaned up), I'd suggest just submitting it for real.
I'll wait for a day for some more comments (e.g. Ingo) and will submit it.
Regards, -velco
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