From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset=US-ASCII From: Daniel Phillips Subject: Re: vmstats patch against 2.4.8pre7 and new userlevel hack Date: Fri, 10 Aug 2001 22:33:31 +0200 References: In-Reply-To: MIME-Version: 1.0 Message-Id: <01081022333100.00293@starship> Content-Transfer-Encoding: 7BIT Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti , lkml Cc: Andrew Morton , Zach Brown , linux-mm@kvack.org List-ID: On Thursday 09 August 2001 08:45, Marcelo Tosatti wrote: > I've updated the vmstats patch to use Andrew Morton's statcount facilities > (which is in initial development state). I've also removed/added some > statistics due to VM changes. I applied it and added some of my own statistics. Very nice, much nicer than the traditional compile-reboot-measure-the-time cycle. For one thing, it means you can watch the system in operation under a test load and see what it's really doing. Chances are, you know right then whether it's running well or not and don't have to wait till the end of a long test run. Problem: none of the statistics show up in proc until the first time the kernel hits them. The /proc/stats entry isn't even there until the kernel hits the first statistic. This isn't user-friendly. I can see that this patch is going to break a lot between kernel updates, because it touches precisely the places we work on all the time - that's why the stats are there, right? I'd suggest breaking it into two patchs, one with all the support and a few basic statistics in stable places, and another that adds in the rest of your current favorite vm stats. It would also be nice if the stats were broken up into sets that can be catted out of proc onto the screen, in other words, sets of 23 or less. This would mean that that something like watch cat /proc/stats/vm is already an effective interface. I already learned a lot more about the what's actually happening inside the vm using this. One thing that surprised me is how few locked pages there actually are on the inactive_dirty list. I suppose I'd need a heavy mmap load to see more activity there. Maybe a heavy write load would show up more there, but for now it looks like there are so few of those locked pages it won't interfere with scanning performance at all. > On the userlevel side, I got zab's cpustat nice tool and transformed it > into an ugly hack which allows me to easily add/remove statistic > counters. I didn't get that to work. It seemed to be looking at the wrong /proc file. I didn't look into it further. -- 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/