Re: Interesting scheduling times - NOT
Jamie Lokier (lkd@tantalophile.demon.co.uk)
Sun, 20 Sep 1998 16:08:44 +0100
On Sat, Sep 19, 1998 at 10:44:34AM +0200, Gabriel Paubert wrote:
> Aren't most of the variables referenced at the same addess modulo 4k since
> they are in the task_state+stack structure ? In this case you repeatedly
> access the same cache set, meaning that your code is a cache thrashing
> benchmark every time you scan a queue with more elements than the L1 cache
> associativity. (And maybe some variables are modified, causing copybacks
> of dirty cache lines, I can't tell, not having access to the source
> right now.)
Aha. Sounds like a good case for SLAB-allocating the task_state
structure separate from the stack. And also varying the initial
kernel stack pointer within the stack pages.
-- Jamie
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