From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 18 Jan 2001 12:32:01 +1100 (EST) From: Rik van Riel Subject: Re: Subtle MM bug In-Reply-To: <87wvburowk.fsf@atlas.iskon.hr> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Zlatko Calusic Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On 17 Jan 2001, Zlatko Calusic wrote: > Rik van Riel writes: > > > > Second test: kernel compile make -j32 (empirically this puts the > > > VM under load, but not excessively!) > > > > > > 2.2.17 -> make -j32 392.49s user 47.87s system 168% cpu 4:21.13 total > > > 2.4.0 -> make -j32 389.59s user 31.29s system 182% cpu 3:50.24 total > > > > > > Now, is this great news or what, 2.4.0 is definitely faster. > > > > One problem is that these tasks may be waiting on kswapd when > > kswapd might not get scheduled in on time. On the one hand this > > will mean lower load and less thrashing, on the other hand it > > means more IO wait. > > Hm, if all tasks are waiting for memory, what is stopping kswapd > to run? :) Suppose you have 8 high-priority tasks waiting on kswapd and one lower-priority (but still higher than kswapd) process running and preventing kswapd from doing its work. Oh .. and also preventing the higher-priority tasks from being woken up and continuing... Rik -- Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com.br/ -- 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.eu.org/Linux-MM/