Messages in this thread | | | Date | Sat, 27 May 2006 21:20:02 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 09/33] readahead: events accounting |
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On Thu, May 25, 2006 at 09:36:27AM -0700, Andrew Morton wrote: > Wu Fengguang <wfg@mail.ustc.edu.cn> wrote: > > > > A debugfs file named `readahead/events' is created according to advises from > > J?rn Engel, Andrew Morton and Ingo Oeser. > > If everyone's patches all get merged up we'd expect that this facility be > migrated over to use Martin Peschke's statistics infrastructure. > > That's not a thing you should do now, but it would be a useful test of > Martin's work if you could find time to look at it and let us know whether > the infrastructure which he has provided would suit this application, > thanks.
Hi, Martin is doing a great job, thanks.
I have read about its doc. It should be suitable for various readahead numbers. And it seems a trivial work to port to it :)
However it might also make sense to keep the current _table_ interface. It shows us the whole picture at a glance:
% cat /debug/readahead/events [table requests] total newfile state context contexta [...] cache_miss 136302 538 3860 11317 490 read_random 62176 160 424 1633 60 io_congestion 0 0 0 0 0 io_cache_hit 34521 663 10071 15611 1423 io_block 204302 42174 10408 68277 2226 readahead 251478 70746 96846 73636 2561 lookahead 136315 14805 86267 32738 2505 lookahead_hit 103384 8038 74605 9097 598 lookahead_ignore 0 0 0 0 0 readahead_mmap 6911 0 0 0 0 readahead_eof 70793 55935 8500 648 581 readahead_shrink 473 0 473 0 0 readahead_thrash 0 0 0 0 0 readahead_mutilt 2526 24 1079 1403 20 readahead_rescue 1209 0 0 0 0
[table pages] total newfile state context contexta cache_miss 1292350444 282817 35557285 86087568 5592690 read_random 10299237 177 426 1903 63 io_congestion 0 0 0 0 0 io_cache_hit 2194663 9289 1507054 414311 184715 io_block 204302 42174 10408 68277 2226 readahead 26122947 770681 21815335 3097682 259587 readahead_hit 23101714 588811 19906233 2209547 191269 lookahead 21397630 173502 19872014 936474 415640 lookahead_hit 18663196 98004 17879848 596562 88782 lookahead_ignore 0 0 0 0 0 readahead_mmap 170509 0 0 0 0 readahead_eof 1950484 432763 1342148 47368 34742 readahead_shrink 19900 0 19900 0 0 readahead_thrash 0 0 0 0 0 readahead_mutilt 220331 485 186922 29900 3024 readahead_rescue 119592 0 0 0 0
[table summary] total newfile state context contexta random_rate 19% 0% 0% 2% 2% ra_hit_rate 88% 76% 91% 71% 73% la_hit_rate 75% 54% 86% 27% 23% var_ra_size 13850 130 5802 6709 10563 avg_ra_size 104 11 225 42 101 avg_la_size 157 12 230 29 166
When Martin's work is included into -mm, I would like to reduce several col/rows from the table to Martin's infrastructure, and perhaps add some more items. One obvious candidate collection is the ra_account(NULL, ...) calls, which do not quite fit the table interface and deserves individual files.
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