Messages in this thread | | | Subject | Re: [PATCH] fix readahead breakage for sequential after random reads | From | Miklos Szeredi <> | Date | Tue, 27 Jul 2004 09:40:20 +0200 |
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Ram Pai <linuxram@us.ibm.com> wrote: > > Also I think the bug that Miklos, found is really hard to reproduce. Did > he find this bug by code inspection? Its really really hard to get into > a state where the current window is of size 1 page with zero pages in > the readahead window, and then the sequential read pattern to just right > then.
I found it by accident. I did my testing with the following read sequence:
page offset num pages 7 1 0 1 35 1 23 1 42 1 33 1 29 1 100 200
I did not measure actual performance, but only looked at the length of the page vector passed to my filesystem's readpages() method.
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