From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Mon, 24 Nov 2003 21:21:39 +0000 Subject: RE: weird speed problem Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Mon, 24 Nov 2003 12:00:09 -0800, "Luck, Tony" said: Tony> You may be able to determine whether this is your problem by Tony> using Stephane's "pfmon" tool to count cache misses at various Tony> levels of the cache hierarchy, and comparing these numbers Tony> from run to run. If you see wildly varying numbers, and your Tony> system is idle apart from the test program, then lack of cache Tony> colouring is probably the issue. Sounds like a good suggestion to me, but before doing that, I'd recommend to collect a simple profile. Just to see if anything obvious is going wrong (like unaligned accesses, lots of fpswa faults, or similar). Hans's qprof tool might come in handy for that: http://www.hpl.hp.com/research/linux/qprof/ Also, I have a not-yet-released tool which can collect call-counts (similar to gprof, but without recompilation). I hope to release it sometime next week or shortly thereafter, but if someone screams loudly enough, I might consider making a quick but totally unsupported snapshot of what I have. --david