From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 20 Dec 2007 11:44:45 -0800 (PST) From: Christoph Lameter Subject: Re: SLUB In-Reply-To: <476A850A.1080807@hp.com> Message-ID: References: <476A850A.1080807@hp.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Mark Seger Cc: linux-mm@kvack.org List-ID: On Thu, 20 Dec 2007, Mark Seger wrote: > This past summer I released a tool on sourceforge called collectl - see > http://collectl.sourceforge.net/ which does some pretty nifty system > monitoring, one component of which is slabs. I finally got around to trying > it out on a newer kernel and I picked 2.6.23 and lo and behold, it didn't work > because /proc/slabinfo has disappeared to be replaced by /sys/slab. I've been Yes. The information available about slabs is different now. > The thing that is especially useful with collectl is that by monitoring slabs > at the same time as monitoring cpu, processes, disk, network and more, you can > get a very comprehensive picture of what's going on at any one time. Good idea. > My main purpose for writing to this list then becomes what would make the most > sense to do with slabs with the new slub allocator? Should I simply report on > these same fields? Are there others that make more sense? Do I need to read > all 184 entries in /sys/slab and then all the entries under them? Clearly I > want to do this efficiently and provide meaningful data at the same time. You only need to read certain files that you need for the information you want to display. > Perhaps someone would like to take this discussion off-line with me and even > collaborate with me on enhancements for slub in collectl? I think we better keep it public (so that it goes into the archive). Here a short description of the field in /sys/kernel/slab/ that you would need -r--r--r-- 1 root root 4096 Dec 20 11:41 object_size The size of an object. Subtract slab_size - object_size and you have the per object overhead generated by alignements and slab metadata. Does not change you only need to read this once. -r--r--r-- 1 root root 4096 Dec 20 11:41 objects Number of objects in use. This changes and you may want to monitor it. -r--r--r-- 1 root root 4096 Dec 20 11:41 slab_size Total memory used for a single object. Read this only once. -r--r--r-- 1 root root 4096 Dec 20 11:41 slabs Number of slab pages in use for this slab cache. May change if slab is extended. -- 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/ . Don't email: email@kvack.org