Messages in this thread | | | Subject | Re: [PATCH 00/23] per device dirty throttling -v8 | From | Andi Kleen <> | Date | 05 Aug 2007 02:26:53 +0200 |
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Ingo Molnar <mingo@elte.hu> writes: > > yeah, it's really ugly. But otherwise i've got no real complaint about > ext3 - with the obligatory qualification that "noatime,nodiratime" in > /etc/fstab is a must. This speeds up things very visibly - especially > when lots of files are accessed. It's kind of weird that every Linux > desktop and server is hurt by a noticeable IO performance slowdown due > to the constant atime updates, while there's just two real users of it: > tmpwatch [which can be configured to use ctime so it's not a big issue] > and some backup tools. (Ok, and mail-notify too i guess.) Out of tens of > thousands of applications. So for most file workloads we give Windows a > 20%-30% performance edge, for almost nothing. (for RAM-starved kernel > builds the performance difference between atime and noatime+nodiratime > setups is more on the order of 40%)
I always thought the right solution would be to just sync atime only very very lazily. This means if a inode is only dirty because of an atime update put it on a "only write out when there is nothing to do or the memory is really needed" list.
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