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KCris1
Beginner
1,294 Views

Perf tools not able to access hardware counters.

I am currently running Ubuntu desktop on my Joule. But, I have the same problem when I run the version of Ostro that has perf tools on it.

When I run perf tools with the following flags, I receive a notification in my output file:

dTLB-load-misses

dTLB-store-misses

iTLB-load-misses

LLC-loads

LLC-load-misses

LLC-stores

LLC-store-misses

L1-icache-loads

L1-icache-load-misses

branch-loads

branch-load-misses

L1-dcache-loads

L1-dcache-load-misses

L1-dcache-stores

L1-dcache-store-misses

According to: http://unix.stackexchange.com/questions/98641/understanding-perf-tool-output http://unix.stackexchange.com/questions/98641/understanding-perf-tool-output my platform doesn't support platform doesn't support some of the processor's performance monitoring unit (PMU) hardware counters. It also says that there may be a way to access the hardware counters somehow. But, I haven't been able to figure it out. Does anyone have any ideas?

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6 Replies
idata
Community Manager
66 Views

Hi keyLey,

 

 

Thank you for contacting us. I tried to use perf using the Ostro image. The output from the command line was that the perf command was not found, so I suspect that you're running this command in Ubuntu, not on Ostro, is this correct? Could you explain how did you install perf on Ostro and what command you used to see the output you posted?

 

 

You also mentioned you're running Ubuntu desktop on the Joule. If that's the case, then I'd suggest you to contact Ubuntu. They're in charge of the Ubuntu image and will be able to provide a more accurate response to anything related to this image. Go to https://developer.ubuntu.com/en/community/ https://developer.ubuntu.com/en/community/ for Ubuntu support.

 

 

We'll be waiting for your response.

 

 

-Sergio A

 

KCris1
Beginner
66 Views

Thank you for getting back to me. Currently, I am using Ubuntu. But, prior to that, I was using the Ostro image. (I did also ask on the Ubuntu forums but I haven't yet received a response.) Before I tried on Ubuntu, though, I tried it on Ostro. Perf is pre-installed in the ostro-xt-image-noswupd-benchmark-qa-intel-corei7-64.dsk image. So, I flashed that .dsk image. When I typed "perf list" to find out which events perf supported, it provided me with the same list of supported events that perf on my current Ubuntu desktop image provides. This leads me to believe that there is some sort of problem accessing some of the hardware counters on the Joule since both operating systems aren't able to access the same counters.

*edited to add that I now realize I asked my question on a different forum than the one you suggested. I will try asking there.

idata
Community Manager
66 Views

Hi keyLey,

 

 

Thank you for your response. I'm unable to see the same output as you after using the perf tools command. Could you let us know the output of cat /etc/*-release?

 

 

We'll be waiting for your response.

 

 

-Sergio A

 

idata
Community Manager
66 Views

Hi keyLey,

 

 

Do you still need assistance on this case? If you do, please reply with the information we requested above.

 

 

We'll be waiting for your response.

 

 

-Sergio A

 

KCris1
Beginner
66 Views

Hello Sergio,

My apologies for the delay - I got a bit swamped last week with other work.

I am working on Ubuntu for now. But, seeing as this is the only forum on which I've received any help, I would still like to try to figure this out.

The perf tools command only lists the supported flags. In order to get the notification, you must actually run perf tools. A command such as the following should do it:

perf stat -r 1 -e LLC-loads,branch-loads ./ 2>

where and are the names/paths of your benchmark executable and your output file, respectively.

I am not sure how to check the cat /etc/*-release.

-Keeley

idata
Community Manager
66 Views

Hi Keeley,

 

 

It's hard to say what your problem is, as we stated above, we were not able to get the same output as you when running the command perf stat. I suspect this is one of the differences between both images. In Ostro, which is the only supported image on Joule, cat /etc/*-release is a command used to see the image version on the Joule. I looked online for errors similar to this one and just as the output suggests, the flag indicates missing support for that particular functionality. Since this is directly related to Ubuntu, we'd still need you to contact Ubuntu again for help. Hopefully, they reply soon with a suggestion that allows you to move forward with your project.

 

 

If you consider moving back to Ostro, we'd be happy to assist you further.

 

 

-Sergio A

 

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