Will, I don't think I replied to this question.
On Tue, Sep 12, 2006 at 02:01:57PM -0400, William Cohen wrote: > Hi All, > > I have an simple-mind Systemtap interface that uses the Perfmon2 Kernel > API to access the counters. The user-space interface automatically loads > the appropriate perfmon module to get access to the performance > monitoring hardware when __pfm_create_context() is performed. When using > the kernel ABI the module does not automatically loaded. What is the > reasoning for this difference in behavior? > This is simple: there cna be a race if you call __pfm_create_context() from the module_init() function. In that case you would be trying to insert a perfmon module while you are inserting yours and you would deadlock on insmod. > If the Perfmon2 KAPI is not available, what are people thoughts on being > able to set up and read the performance counters within the kernel? What > about being ability for the kernel to monitor itself? For now, I have pulled the kapi support out of the new code base in an effort to ease the situation a little bit and until we can make a very strong case for it. -- -Stephane _______________________________________________ perfmon mailing list [email protected] http://www.hpl.hp.com/hosted/linux/mail-archives/perfmon/
