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 15:41:16 +0200 References: <20810000.1026311617@baldur.austin.ibm.com> <20020710173254.GS25360@holomorphy.com> <3D2C9288.51BBE4EB@zip.com.au> In-Reply-To: <3D2C9288.51BBE4EB@zip.com.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton , William Lee Irwin III Cc: Rik van Riel , Dave McCracken , Linux Memory Management List-ID: On Wednesday 10 July 2002 22:01, Andrew Morton wrote: > Bill, please throw away your list and come up with a new one. > Consisting of workloads and tests which we can run to evaluate > and optimise page replacement algorithms. I liked the list, I think it just needs to be reorganized. All the vaporware needs to go into an "enables" section (repeating myself) and it needs to aquire a 'disadvantages' section, under which I'd like to contribute: - For pure computational loads with no swapping, incurs unavoidable) overhead on page setup and teardown (measure it) - Adds new struct page overhead of one word, plus two words per shared pte (share > 1) (measure this) - Introduces a new resource, pte chain nodes, with associated locks and management issues (show locking profiles) - Is thought to cause swap read fragmentation (demonstrate this, if possible) And an advantage to add to Bill's 'enables' list: - Enables a swap fragmentation reduction algorithm based on finding virtually adjacent swapout candidates via the pte_chains > Alternatively, please try to enumerate the `operating regions' > for the page replacement code. Then, we can identify measurable > tests which exercise them. Then we can identify combinations of > those tests to model a `workload'. We need to get this ball > rolling somehow. Strongly agreed that the focus has to be on workload modeling. We should be able to organize the modeling strictly around the advantages/disadvantages list. -- 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/