Messages in this thread | | | Date | Mon, 21 Apr 2003 21:14:33 -0700 | From | "Martin J. Bligh" <> | Subject | Re: 67-mjb2 vs 68-mjb1 (sdet degredation) |
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>> > Here's a backout patch. Does it fix it up? >> >> Yeah, that fixes it. Ho hum ... I wonder if we can find something that >> works well for both cases? I guess the options would be: >> >> 1. Some way to make the rwlock mechanism itself faster. >> 2. Try to fix the contention itself somehow for this instance. > > You're using PIII's, which don't mind the additional buslocked operation. > P4's hate it. We'd need to retest on big P4 and other architectures to > decide.
OK, I can try do get someone to test on big x440s (P4 Xeon).
> I suspect the spinlock is better that the rwlock overall - having multiple > CPUs looking up things in the same address_space is relatively uncommon. > Having one CPU looking things up in one address space is very common, and > that's the thing which the s/rwlock/spinlock/ speeds up.
Yeah, wasn't really complaining - I think the spinlock is the right thing to do ... I just wanted to nail down what caused it, and be sure it was deliberate. Looks like it is, so that all seems OK. Thanks for the help ;-)
M.
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