RE: Problems with oprofile 0.9.6

[Martin C. M. <mmartin@Endeca.com>]

Thanks a lot Maynard.

/dev/oprofile is empty:

$ sudo ls /dev/oprofile/

$ sudo ls /dev/oprofile/cpu_type
ls: cannot access /dev/oprofile/cpu_type: No such file or directory

It's not a VM, but a bare metal machine.

Apparently I have a bunch of offline processors.  I guess my motherboard
supports them or something:

$ cat /sys/devices/system/cpu/online
0-11

$ cat /sys/devices/system/cpu/offline
12-31

What would cause an empty /dev/oprofile?  I've rebooted recently.  I
could re-install oprofile and reboot if you think that would help.

Thanks,
Martin

-----Original Message-----
From: Maynard Johnson [mailto:may...@us...] 
Sent: Wednesday, June 22, 2011 11:05 AM
To: Martin C. Martin
Cc: opr...@li...; Andi Kleen
Subject: Re: Problems with oprofile 0.9.6

Martin C. Martin wrote:
> Hi,
> 
>  
> 
> I'm unable to get oprofile to produce a profile.  My oprofiled.log
> shows:
> 
>  
> 
> -- OProfile Statistics --
> 
> Nr. sample dumps: 34
> 
> Nr. non-backtrace samples: 0
> 
> Nr. kernel samples: 0
> 
> Nr. lost samples (no kernel/user): 0
> 
> Nr. lost kernel samples: 0
> 
> Nr. incomplete code structs: 0
> 
> Nr. samples lost due to sample file open failure: 0
> 
> Nr. samples lost due to no permanent mapping: 0
> 
> Nr. event lost due to buffer overflow: 0
> 
> Nr. samples lost due to no mapping: 0
> 
> Nr. backtraces skipped due to no file mapping: 0
> 
> Nr. samples lost due to no mm: 0
> 
>  
> 
> ---- Statistics for cpu : 31
> 
> Nr. samples lost cpu buffer overflow: 0
> 
> Nr. samples received: 0
> 
> Nr. backtrace aborted: 0
> 
> Nr. samples lost invalid pc: 0
> 
>  
> 
> and so on for 32 CPUs.
> 
>  
> 
> Any ideas for what I can do to track this down?
> 
>  
> 
> One oddity is that I only have 6 cores, and even with hyperthreading
> that's 12 cpus.  /proc/cpuinfo confirms 12 cpus.
> 
>  
> 
> opcontrol -list-events prints:
> 
>  
> 
> $ opcontrol --list-events
> 
> oprofile: available events for CPU type "Intel Architectural Perfmon"
> 
>  
> 
> See Intel 64 and IA-32 Architectures Software Developer's Manual
> 
> Volume 3B (Document 253669) Chapter 18 for architectural perfmon
events
> 
> This is a limited set of fallback events because oprofile doesn't know
> your CPU
> 
> CPU_CLK_UNHALTED: (counter: all)
> 
>         Clock cycles when not halted (min count: 6000)
> 
> INST_RETIRED: (counter: all)
> 
>         number of instructions retired (min count: 6000)
> 
> LLC_MISSES: (counter: all)
> 
>         Last level cache demand requests from this core that missed
the
> LLC (min count: 6000)
> 
>         Unit masks (default 0x41)
> 
>         ----------
> 
>         0x41: No unit mask
> 
> LLC_REFS: (counter: all)
> 
>         Last level cache demand requests from this core (min count:
> 6000)
> 
>         Unit masks (default 0x4f)
> 
>         ----------
> 
>         0x4f: No unit mask
> 
> BR_INST_RETIRED: (counter: all)
> 
>         number of branch instructions retired (min count: 500)
> 
> BR_MISS_PRED_RETIRED: (counter: all)
> 
>         number of mispredicted branches retired (precise) (min count:
> 500)
> 
>  
> 
> My work flow is:
> 
>  
> 
> sudo opcontrol --shutdown
> 
> sudo opcontrol --init
> 
> sudo opcontrol --setup --no-vmlinux --callgraph=0
> --event=CPU_CLK_UNHALTED:100000 --image=all
> 
> sudo opcontrol --start-daemon
> 
> sudo opcontrol --reset
> 
> sudo opcontrol --start --separate=lib
> 
> (Fire up python and run an infinite loop, let it run for a few seconds
> then kill it)
> 
> sudo opcontrol --stop
> 
> sudo opcontrol --dump
> 
> opreport
> 
>  
> 
> opreport says:
> 
>  
> 
> opreport error: No sample file found: try running opcontrol --dump
> 
> or specify a session containing sample files
> 
>  
> 
> $ sudo cat /root/.oprofile/daemonrc
> 
> SESSION_DIR=/var/lib/oprofile
> 
> CHOSEN_EVENTS_0=CPU_CLK_UNHALTED:100000:0:1:1
> 
> NR_CHOSEN=1
> 
> SEPARATE_LIB=1
> 
> SEPARATE_KERNEL=0
> 
> SEPARATE_THREAD=0
> 
> SEPARATE_CPU=0
> 
> VMLINUX=none
> 
> IMAGE_FILTER=
> 
> CPU_BUF_SIZE=0
> 
> CALLGRAPH=0
> 
> XENIMAGE=none
> 
>  
> 
> This is on Ubuntu 10.10.
> 
>  
> 
> Is there any documentation or wiki page on how to track down these
> problems?  Or is this mailing list my best bet?

This mailing list is the best place to get help.  What's the cpu_type as
shown in /dev/oprofile/cpu_type?  There may be some kernel config option
or boot option needed to enable profiling for your specific processor
type.  If so, I think Andi (on cc) could help with that.

As for the number of processor entries in the oprofiled.log . . . that's
determined by the number of cpu<x> directories found in
/dev/oprofile/stats.  Those directories are created by the oprofile
kernel driver based on what it sees from the kernel macro
'for_each_possible_cpu'.  So look at /sys/devices/system/cpu/online and
/sys/devices/system/cpu/offline.

-Maynard

> 
>  
> 
> Thanks,
> 
> Martin
> 
> 
> 
> 
> 
>
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