Messages in this thread | | | Date | Thu, 20 Feb 2003 23:19:27 -0800 | From | "Martin J. Bligh" <> | Subject | Re: Strange performance change 59 -> 61/62 |
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>> I'm comparing 59-mjb6 to 61-mjb1 and notice some strange performance >> differences that I can't explain ... not a big drop, but odd. >> ... >> >> 1562 .text.lock.file_table >> 583 dentry_open >> 551 get_empty_filp > > The first one here is fget(). That's causing problems on ppc64 as well - the > machine is spending as long in fget as it is in copy_foo_user() in dbench > runs. > > One possibility is that we're calling fget() more often than previously, > although that would be rather odd. Can you add the below patch, and monitor > /proc/meminfo:nr_fgets?
Thanks for the patch, sorry it took me so long to get the testing done.
59: 4742165 61: 4743166
Pretty damned close ;-)
> If not that, then maybe some funny cacheline aliasing thing?
Mmm... you mean like something sharing the cacheline with the file lock?
M.
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