From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 11 Aug 2001 13:57:10 -0300 (BRT) From: Marcelo Tosatti Subject: Re: vmstats patch against 2.4.8pre7 and new userlevel hack In-Reply-To: <01081022333100.00293@starship> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Daniel Phillips Cc: lkml , Andrew Morton , Zach Brown , linux-mm@kvack.org List-ID: On Fri, 10 Aug 2001, Daniel Phillips wrote: > 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. Right. This has to be fixed. > 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? Exactly. Thats why I've thought about doing the thing in an easy way to remove/add new statistics. Kudos goes to Andrew for the statcount code. Thanks a lot! > 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. The default /proc file it tries to open is "/proc/vm_stat", while the stats are at "/proc/stats/vm". Use the -p option to select the file to read the stats from. (nvmstat -p /proc/stats/vm) The userlevel tool will average the stats, so you can actually see whats happening over time, and not just see "what already happened". Its really really useful. -- 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/