From: Maynard J. <may...@us...> - 2010-09-23 14:02:43
|
On 09/23/2010 5:50 AM, C K Kashyap wrote: > Hi, > I was wondering if I've missed any setting/flag to get the kernel > callgraph correctly? > > On Fri, Sep 17, 2010 at 12:05 PM, C K Kashyap<ckk...@gm...> wrote: >>> What oprofile version are you using and what's your architecture and >>> processor type? Callgraph is not supported on all architectures. Some >>> examples where it *is* supported are: x86, ppc64, and ARM. >>> >> My kernel/OS details as follows - >> Linux mymachine 2.6.18-128.el5 #1 SMP Wed Dec 17 11:41:38 EST 2008 >> x86_64 x86_64 x86_64 GNU/Linux >> >> Oprofile version - opcontrol: oprofile 0.9.3 compiled on Sep 3 2008 00:41:52 >> >> Some data about the hardware - >> vendor_id : GenuineIntel >> cpu family : 6 >> model : 23 >> model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz >> >> >> So, I am able to generate callgraph for user apps. Its the kernel >> where I dont see goot result. Yes, sorry, that slipped by me -- the snippet of opreport you pasted into your note seemed to imply that neither userspace nor kernelspace callgraph'ing was working. Please provide the final stats reported in the oprofiled.log. That will help us determine if this is an oprofile userspace issue or an oprofile kernel driver issue. It may not be definitive . . . we may have to dig deeper by collecting verbose output. But running with --verbose even without callgraph enabled can severely impact results due to the high overhead. Then when you add the high overhead of callgraph, verbose enablement can result in so many lost samples that it's almost useless without careful tweaking of buffer sizes and sampling frequencies. *Robert*, have you heard of anything like this before? -Maynard >> >> Regards, >> Kashyap >> > > > |