Re: Regarding vmlinux file for opcontrol --init

I installed oprofile-1.1.0. When I executed ophelp -r command, it gave me
output as 'Intel Broadwell Microarchitecture as output'.

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.

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
>>
>>
>>
>>
>>
>

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