On 02/28/2012 05:27 PM, Ming Lei wrote:
OK, could you try the MLO and u-boot.bin under the link of http://kernel.ubuntu.com/~ming/up to see if 'perf' may work well?
Is it really possible that the bootloader stuff affects perf/oprofile?
If still not, could you tell me what is the revision of your pandaboard?
The kernel and u-boot says that CPU is OMAP4430 ES2.2, the board box has the label with PANDABOARD UEVM4430G-01-00-00, and /proc/cpuinfo is shown below.
Processor : ARMv7 Processor rev 2 (v7l) processor : 0 BogoMIPS : 597.81
processor : 1 BogoMIPS : 597.81
Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x1 CPU part : 0xc09 CPU revision : 2
Hardware : OMAP4 Panda board Revision : 0020 Serial : 0000000000000000
or do you have any changes on the hardware?
No.
I am sure that several guys have tried the current omap4 pmu patch and make perf work well on pandaboard.
Perf (in particular, "perf top") works for me too. Also I tried "perf record -a -F 1000 sleep 200" while running the kernel module workload, and have never seen "nobody cared" IRQ issues. You have said that oprofile uses perf subsystem as a backend, so this looks even more strange.
Dmitry