Re: kernel thread support - LWP's

Stephen C. Tweedie (sct@redhat.com)
Mon, 19 Jul 1999 14:44:32 +0100 (BST)


Hi,

On Sun, 18 Jul 1999 22:07:21 +0200, Andi Kleen <ak@muc.de> said:

> Also with the lazy tlb flushing 2.3 has now a context switch between
> threads that share VM is not much more than a function call now.

We've always had that: we don't reset %cr3 when we do a thread switch,
which avoids the tlb hit.

The lazy TLB code in 2.3 is something very different. It means that for
threads which do not access user mode data at all for a while, but which
still schedule a lot, we don't switch the page tables at all when
scheduling that thread. So, when we enter the idle thread, for example,
or when we trigger the bdflush thread, we avoid a hardware context
switch (and similarly we avoid it when we switch back to the previous
thread).

--Stephen
`

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/