From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Fri, 08 Mar 2002 17:31:49 +0000 Subject: Re: [Linux-ia64] VHPT performance 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 Fri, 08 Mar 2002 11:26:33 +0100, Christian Hildner said: Christian> Ok that's true. I changed my program so that before the Christian> measuring loop there comes the same loop for filling the Christian> cache. Also I had to increase the memory size to a Christian> minimum of 128 pages because for itanium there are 32 Christian> entries for L1-DTLB and 96 entries for L2-DTLB. Now I get Christian> values of 42 cycles with VHPT enabled and 180 cycles with Christian> VHPT disabled. This values are coming near to the ones Christian> you found. Great! Two other things you may want to try: o Use a stride of PAGE_SIZE+LINE_SIZE. This reduces the likelihood of exceeding the cache associativity. o Rather than calling printf() in each iteration, collect the results in an array and print them once the test is done. printf() is a monster and will blow away a good portion of the first level caches as well as a couple of TLB entries. --david