From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="iso-8859-1" From: Daniel Phillips Subject: Re: [PATCH] Optimize out pte_chain take three Date: Sat, 13 Jul 2002 16:45:38 +0200 References: <20810000.1026311617@baldur.austin.ibm.com> <3D2C9288.51BBE4EB@zip.com.au> <20020710222210.GU25360@holomorphy.com> In-Reply-To: <20020710222210.GU25360@holomorphy.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III , Andrew Morton Cc: Rik van Riel , Dave McCracken , Linux Memory Management List-ID: On Thursday 11 July 2002 00:22, William Lee Irwin III wrote: > As far as operating regions for page replacement go I see 3 obvious ones: > (1) lots of writeback with no swap > (2) churning clean pages with no swap > (3) swapping Another big variable is the balance of streaming IO versus program workload. Within streaming IO there is the read/write balance (starting to get away from core VM here). There's also the balance of file cache activity vs anonymous memory. It goes on of course - we have to boil this down to a few reasonably orthogonal variables. Your specific load examples can be thought of as specific points in a two-dimensional test model with two variables: - Total working set relative to physical memory (should range from significantly less to significantly more) - Balance of read accesses vs write accesses Adding up the above, there are 5 knobs to turn so far. This whole thing sounds like it can be modeled elegantly by a couple of C programs, one to generate memory loads and another to generate file loads, or we may be able to identify an off-the-shelf benchmark program that provides some of the tunables we need. Needless to say, we need more than one or two points on each axis. We need to capture our data in some organized way. How? Clearly, this benchmarking project as I've described it is starting to blow up into unreasonable dimensions. I'd like to return to the idea of going through the original list of advantages and disadvantages item by item and identifying exactly which variables in our complete test space are relevant. This lets us set the knobs on our test programs, define the test, and know which numbers we want to capture/graph. -- Daniel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/