Vivek, On Tue, Oct 02, 2007 at 01:59:12PM -0400, [EMAIL PROTECTED] wrote: > > I have to start and stop monitoring multiple times in my program and I am > using perfmonctl (the older interface) to do that. But I find that the > perfmonctl(PFM_START,....) gives me an error starting from the second call. > > So, abstractly my sequence is : > > start loop: > ... > perfmonctl(PFM_START,...) > > > < Some code used to monitor the hw counters > > > > perfmonctl(PFM_STOP,...) > > goto start_loop: > > It happens that if i don't have a lot of code in between, then everything is > fine, i get all the overflow interrupts that i want. However, normally my > iteration takes around 12 seconds after which i find that the > perfmonctl(PFM_START,...) fails with invalid argument as the error. There is > only argument of relevance which is pfm_fd. Can you suggest me what could be > the cause of this ? > Are you using a kernel-level sampling buffer or are you handling this completly at the user level?
I can see a problem if you issue PFM_START and you have a pending overflow. I will go back to the code and check this. There maybe a bug there or a special case to handle. This is an interesting issue. Thanks. -- -Stephane _______________________________________________ perfmon mailing list [email protected] http://www.hpl.hp.com/hosted/linux/mail-archives/perfmon/
