Messages in this thread |  | | Date | Sun, 31 Dec 2000 09:12:21 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [RFC] Generic deferred file writing |
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On Sun, 31 Dec 2000, Alexander Viro wrote: > > On Sun, 31 Dec 2000, Linus Torvalds wrote: > > > The other thing is that one of the common cases for writing is consecutive > > writing to the end of the file. Now, you figure it out: if get_block() > > really is a bottle-neck, why not cache the last tree lookup? You'd get a > > 99% hitrate for that common case. > > Because it is not a bottleneck. The _real_ bottleneck is in ext2_new_block(). > Try to profile it and you'll see. > > We could diddle with ext2_get_block(). No arguments. But the real source of > PITA is balloc.c, not inode.c. Look at the group descriptor cache code and > weep. That, and bitmaps handling.
I'm not surprised. Just doign pre-allocation 32 blocks at a time would probably help. But that code really should be re-written, I think.
Linus
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