On Fri, Jan 10, 2003 at 05:35:56PM -0500, Andrew Cagney wrote:
>We don't use the straw on some targets now; Linux (need to get back to
>that patch and turn it on always!), *BSD.
Right so that 32 byte read is now cheap.
>The dcache needs some serious work if you want it to be always on.
>Last time I tested it it caused an actual slowdown. Basically, it's
>too small to be useful.
>
>#define DCACHE_SIZE 64
>#define LINE_SIZE_POWER (5)
>
>So it never stores more than 2K. LinuxThreads _overwhelms_ that, by a
>downright boggling amount.
You wouldn't know why it caused a slow down? Th 32 byte read should now
be cheaper.
This was before the 32-byte-read support. So we read lines in, did
more computation than before, and overwrote them in the cache; exactly
the same I/O, more CPU.
Well, possibly more I/O. And, I think, the I/O / context switch / ...
is the expensive part.