perf_event_open syscall fails for HW counters on Pandaboard

[Marat Dukhan]

On Pandaboard perf_event_open syscall fails with errno = 19 (ENODEV) when trying to open perf counter with type PERF_TYPE_HARDWARE.

The code to reproduce the error is attached. I checked that it runs successfully on Beagleboard, Sandy Bridge, Bulldozer systems, and even on Pandaboard if I request software events (e.g. type = PERF_TYPE_SOFTWARE, config = PERF_COUNT_SW_CPU_CLOCK).

Linux Kernel (uname -a): Linux pandaboard 3.2.0-1418-omap4 #25-Ubuntu SMP PREEMPT Fri Aug 31 18:41:31 UTC 2012 armv7l armv7l armv7l GNU/Linux
Distribution: Ubuntu Server 12.04
Loaded kernel modules (lsmod): cpufreq_powersave, cpufreq_conservative, cpufreq_userspace, cpufreq_ondemand, dm_crypt, wl12xx_sdio, wl12xx, mac80211, twl6040_vibra, ff_memless, cfg80211, leds_gpio
Kernel log (dmesg): contains message "hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, 7 counters available"
/proc/cpuinfo content:
Processor : ARMv7 Processor rev 10 (v7l)
processor : 0
BogoMIPS : 696.39

processor : 1
BogoMIPS : 681.68

Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x2
CPU part : 0xc09
CPU revision : 10

Hardware : OMAP4 Panda board
Revision : 0020
Serial : 0000000000000000

[Marat Dukhan (maratek)]

The code to reproduce the bug

[Marat Dukhan (maratek)]

Linux kernel log

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1048056

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Marat Dukhan (maratek)]

apport-collect crashes on my Pandaboard.

[David Long (dave-long)]

I do not see this problem on a kernel built from the latest Linaro TI 3.2 sources using the default config file. The error sounds like a configuration error, or possibly a problem in the underlying hardware event support which has been patched over time.

If you are intent on continuing with a 3.2 kernel I recommend rebuilding it from sources checked out from the origin/tilt-3.2 tracking branch in the git://git.linaro.org/landing-teams/working/ti/kernel.git repo. Either use the omap4_defconfig under there or at least make sure CONFIG_HW_PERF_EVENTS=y is present.

[warmcat (andy-warmcat)]

What's the situation with it on tilt-3.4? 3.2 is too old to care about but 3.4 needs to work under the same conditions.

[David Long (dave-long)]

A fresh build of 3.4 from the origin/tilt-3.4 tracking branch also works.