Re: Regarding vmlinux file for opcontrol --init

Hi,

I checked the status of PMU. Referring to log, I found a note as :



*Performance Events: unsupported p6 CPU model he 61 no PMU driver, software
events only.*
61 is my CPU model No.

As per my study, if I am not wrong this is given by linux, not Xen . Due to
this probably PMU is not getting enabled.

Can you help me out in solving this?

Thanks


On Tue, Feb 28, 2017 at 6:20 PM, Michael Petlan <[email protected]> wrote:

> On Tue, 28 Feb 2017, dhara buch wrote:
>
>> I installed oprofile-1.1.0. When I executed ophelp -r command, it gave me
>> output as 'Intel Broadwell Microarchitecture as output'.
>>
>
> This is correct. The CPU has been detected correctly.
>
>
>> Then I executed operf command without any option, but it gave me an error
>> as follows:
>> ou
>> Your kernel's performance event subsystem does not support your processor
>> type.
>>
>
> It looks like the VM guest has no access to the HW counters.
> Xen should be able to support it, however, I don't have any
> experience with Xen, thus nor with running OProfile there.
>
> Google says that you need to boot with 'vpmu=1'. Or try to
> search for "enable PMU in Xen guests" or similar.
>
> You can verify that PMU is working by:
>
> $ ocount ls
> Events were actively counted for 2669610 nanoseconds.
> Event counts (actual) for /usr/bin/ls:
>         Event                   Count                    % time counted
>         cpu_clk_unhalted        3,982,864                100.00
>
> or using perf (linux-tools package), by
>
> $ perf stat -e cycles ls
>  Performance counter stats for 'ls':
>          3,737,940      cycles
>        0.013856521 seconds time elapsed
>
> I think this should work without any necessary patches if
> you enable PMU for the guest.
>
> Cheers,
> Michael
>
>
>
>> What is the solution?
>>
>> Thank y
>>
>> On Tue, Feb 28, 2017 at 12:40 PM, dhara buch <[email protected]>
>> wrote:
>>
>>       ---------- Forwarded message ----------
>>       From: Michael Petlan <[email protected]>
>>       Date: Tue, Feb 28, 2017 at 12:00 AM
>>       Subject: Re: Regarding vmlinux file for opcontrol --init
>>       To: dhara buch <[email protected]>
>>       Cc: [email protected]
>>
>>
>>       On Mon, 27 Feb 2017, dhara buch wrote:
>>             Hello,
>>
>>             Thanks a lot for the prompt reply.
>>
>>
>>       Hi, you're welcome. Please do Reply-To-All to make sure it all
>>       goes also to [email protected] --> others
>>       might appreciate the list history for solving similar problems
>>       in future.
>>
>>
>>             I am using i7 core processor. When I executed ophelp -r, the
>> displayed CPU type was  'Intel Architectural Perfmon'.
>>
>>
>>       The "Core i7" is too generic nomenclature. Could you please send
>>       the output of `lscpu` or attach /proc/cpuinfo (one core is enough)?
>>       The important fields are cpu model and cpu family:
>>
>>       Vendor ID:             GenuineIntel
>>       CPU family:            6
>>       Model:                 78
>>
>>             Afterwards, when I execute opcontrol --vmlinux=(uncompressed
>> form of vmlinuz) command, the CPU type gets changed to 'CPU with timer
>> Interrupt'.
>>
>>             The problem would be in uncompressed file? I am also not much
>> clear about the proper way to get vmlinux from vmlinuz file.
>>
>>
>>       I think you decompressed the file correctly. However, this does
>>       not affect the CPU identification/understanding.
>>
>>       Regarding to vmlinux:
>>
>>       You can even skip vmlinux by using "--no-vmlinux" switch with
>>       opcontrol. That will mark all the samples captured in kernel as
>>       "no-vmlinux" and no vmlinux file is needed. However, this is no
>>       good if you want to profile kernelspace.
>>
>>       Your problem is that your CPU is not identified by OProfile.
>>       If you send me the `lscpu` output or the /proc/cpuinfo file
>>       contents, I might figure out why.
>>
>>       However, it is very probable, that your CPU is supported by the
>>       latest OProfile 1.1 and I encourage you to try that one instead.
>>
>>       ------------
>>
>>       Some deeper explanation:
>>
>>       There are two modes oprofile knows, let's call them "opcontrol-mode"
>>       and "operf-mode".
>>
>>       --
>>
>>       1) "opcontrol-mode" is obsolete and consists of a kernel module,
>>       a profiling daemon and a controller (opcontrol). By this controller,
>>       you signal the profiling daemon to start/stop/reset profiling, etc.
>>
>>       The event sources can be either HW events or TIMER interrupt. The
>>       TIMER interrupt is a fallback used by the daemon when HW events are
>>       not detected. They are not detected when the CPU is unknown or not
>>       supported. It might be also totally different architecture which
>>       does not support any HW events, or, the HW events might be disabled
>>       (e.g. you are running a virtual machine and the hypervisor does not
>>       support/enable that for its guests).
>>
>>       The "TIMER interrupts" is a software-emulated event that is used
>>       when the HW events are simply not available.
>>
>>       Also note, that the TIMER interrupts ARE NOT SUPPORTED in the
>> "operf-
>>       mode". So using "TIMER interrupts" might be a reason why a user
>> might
>>       want to stick with this legacy "opcontrol-mode".
>>
>>       The "opcontrol-mode" has been removed from OProfile 1.0, so 0.9.9 is
>>       the latest OProfile that supports it.
>>
>>       --
>>
>>       2) "operf-mode" is far better replacement for the previous mode. It
>>       does not need any daemon and kernel module, the usage is much more
>>       simple and it has lots of other advantages.
>>
>>       Basically, the only disadvantage is that it does NOT support the
>>       TIMER interrupts fallback. Thus, when the HW events are not enabled/
>>       detected/usable/supported/etc, you cannot fallback to the TIMER
>> mode.
>>
>>       If you do not want to use the TIMER mode, there is basically no
>>       reason for not using "operf-mode" instead, thus there is nothing to
>>       be lost by updating to oprofile-1.1.
>>
>>       --------------------
>>
>>       So, I recommend to update to the latest OProfile and try out the
>>       operf mode:
>>
>>       1) `ophelp -r` should still test the CPU identification
>>
>>       I believe, your CPU will be supported after updating, but I cannot
>>       be sure without knowing the model/family numbers.
>>
>>       2) `ocount ls` should report some numbers (this tests whether the
>>       HW events can be used).
>>
>>       3) `ophelp | less` will print all the HW events available to you
>>
>>       4) Basic profiling:
>>
>>       operf ls
>>       opreport
>>
>>       5) or let's profile systemwide and with kernel:
>>
>>       operf -s --vmlinux /your/path/to/vmlinux
>>       # wait here for a while
>>       ^C
>>       opreport
>>
>>       ------------------------
>>
>>       Hope it helps.
>>       Michael
>>
>>
>>             Dhara Buch
>>
>>             On Mon, Feb 27, 2017 at 10:24 PM, Michael Petlan <
>> [email protected]> wrote:
>>                   On Mon, 27 Feb 2017, dhara buch wrote:
>>                         Hello,
>>
>>
>>                   Hi Dhara,
>>
>>
>>                         I have installed Oprofile-0.9.9 on Ubuntu 15.10.
>> I try to init oprofile with'
>>                         opcontrol --init command, which requires
>> uncompressed vmlinux file with --vmlinux option.
>>
>>                         I have tried to uncompress the present vmlinuz
>> with extract-vmlinux script. The file gts uncompressed,but when I init
>> opcontrol with this uncompressed
>>             file, my CPU
>>                         type gets wrongly
>>                         identified. Hence, although the hardware events
>> are supported by the processor, 'timer' mode gets set and event monitoring
>> doesn't become possible.
>>
>>
>>                   You can test the CPU identification by running `ophelp
>> -r` which should
>>                   print what OProfile thinks your CPU is, such as:
>>
>>                   $ ophelp -r
>>                   Intel Skylake microarchitecture
>>
>>                   What is your CPU type? OProfile 0.9.9 is pretty old, it
>> might not support
>>                   the newer processors. Consider using the latest
>> OProfile 1.1. It might not
>>                   fit you if you need the legacy opcontrol-based
>> profiling mode (which was
>>                   removed from 1.0 and above), but since you probably
>> want to use the CPU
>>                   hardware events, I guess, operf-mode (and oprofile-1.1)
>> should serve you
>>                   well.
>>
>>                   Regards,
>>                   Michael
>>
>>
>>                         I would be thankful if anybody can guide me to
>> solve this problem.
>>
>>                         Dhara Buch
>>
>>
>>
>>
>>
>>
>>
>>

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot

_______________________________________________
oprofile-list mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/oprofile-list