Re: Using kprobes [was Re: [PATCH] Performance Stats: Kernel patch
From: Christoph Hellwig <hch@lst.de>
Date: 2007-05-12 09:17:51
On Fri, May 11, 2007 at 12:23:04PM -0500, Linas Vepstas wrote:
On Thu, May 10, 2007 at 11:12:42AM -0700, Andrew Morton wrote:quoted
I don't think the syscall-counting feature has a future, sorry. Perhaps you could do something like hooking it up on-demand by insertion of a kprobe, dunno.This is an interesting point. I've started fiddling with (a wrapper around) kprobes that allows me to pick any subroutine symbol in System.map, and then get an event whenever that subroutine gets called. Its pretty slick, and allows me to gather data on certain unusual events in the kernel. (I'm not using this for performance monitoring, I'm trying to do RAS). It makes a lot of sense to me to have a generic kprobe extension, where you could give it a list of subroutine names, and it'll collect stats on the number of times that the routine was called. Some user-space thingy could poll for those stats, or you could put them in /sys or wherever. Its more complicted than just instriumenting syscalls, but a lot more useful, I would think ...
Yes, this is exactly the useful kind of kprobes useage we should have in the tree.
--linas _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
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