From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DiyIa-0000w8-8F for user-mode-linux-devel@lists.sourceforge.net; Thu, 16 Jun 2005 10:37:04 -0700 Received: from dgate1.fujitsu-siemens.com ([217.115.66.35]) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.41) id 1DiyIZ-0001p7-LT for user-mode-linux-devel@lists.sourceforge.net; Thu, 16 Jun 2005 10:37:04 -0700 Message-ID: <42B1B8B9.7070006@fujitsu-siemens.com> From: Bodo Stroesser MIME-Version: 1.0 Subject: Re: [uml-devel] Recent patches of note References: <20050616160728.GA6040@ccure.user-mode-linux.org> In-Reply-To: <20050616160728.GA6040@ccure.user-mode-linux.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Thu, 16 Jun 2005 19:36:57 +0200 To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net Jeff Dike wrote: > I'd like to call attention to some recent patches that may be of interest > to people before they hit mainline. These are all on my incremental patches > page, http://user-mode-linux.sf.net/patches.html > > First, sched-starve (http://user-mode-linux.sourceforge.net/work/current/2.6/2.6.12-rc6-mm1/patches/sched-starve) > > This fixes a timer initialization botch which resulted in soft lockup > warnings in recent kernels, total non-responsiveness (i.e. nothing > else would be scheduled) under any workload which avoided idling the > kernel, and may be responsible for the load average >= 1 problem. > > I don't see that last here for some reason, so I'd like some > confirmation (or not) that this patch fixes that. > > Second, I implemented soft interrupts, which reimplements interrupt > enabling and disabling with a flag rather than with sigprocmask. This > cuts down hugely on the number of system calls that UML makes, > resulting in a very noticable performance increase. This patch, plus > the other system call reducing patches which immediately follow it, > speed up my kernel builds by 20-25%. By far the largest piece of this > is softints, although skas-no-flush-kernel also is noticable. Great! > > I'd like people to check out softints, at least, and report any > problems. It's running fine here, but interrupt handling is a > sensitive area, so I'd like to know people are running it without > problems before pushing it to mainline. > > Jeff Currently my time is *very* limited, so I can't test. Reading the patches only the one that makes me worry is "dont-save-fpregs". To not save fpregs on every syscall or interrupt is O.K. But you also have to modify signal-handling, that currently relies on fpregs being saved. And you have to save and restore fpregs in switch_to for SKAS3 and also for SKAS0, if processes share the same mm. Then, I think special handling is needed for the fpregs in copy_thread and probably in execve also. Bodo ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel