[Intel-gfx] Supporting Intel GPU tracing in gpuvis

[Tvrtko Ursulin]

Hi,

On 16/11/2017 20:42, Michael Sartain wrote:
> On Wed, Sep 6, 2017, at 02:09 AM, Chris Wilson wrote:
>> Quoting Daniel Vetter (2017-09-06 08:46:50)
>>> Hi Pierre,
>>>
>>> On Tue, Sep 5, 2017 at 11:15 PM, Pierre-Loup A. Griffais
>>> <pgriffais at valvesoftware.com> wrote:
>>>> Hi Daniel,
>>>>
>>>> In the past couple of months we've been working on gpuvis, a GPU tracing
>>>> tool similar to GPUView on Windows. It's lower level than other API-based
>>>> tracing tools and lets you debug system-wide GPU scheduling issues, eg.
>>>> interaction between several processes using the GPU, which is pretty
>>>> critical for VR usecases.
>>>>
>>>> It's all based on ftrace; we've initially developped it with support for
>>>> amdgpu, and had to patch the kernel code there to change what tracing events
>>>> are reported and how. Now that we have a good idea of what's needed and it's
>>>> more or less proven in production, we were wondering if you had any interest
>>>> in adding a similar set of events for Intel GPUs so we could read them and
>>>> present them the same way? We have pretty specific requirements, but this
>>>> work-in-progress documentation should give a good idea of what they are:
>>>>
>>>> https://github.com/mikesart/gpuvis/wiki/Overview
>>
>> We already have those tracepoint equivs and a script to generate a
>> similar visualisation: intel-gpu-tools/scripts/trace.pl, but only
>> looking at the scheduling issue from the gpu pov. But it's really only a
>> dev toy atm, plugging the gap between userspace and the gpu has been on
>> the perennial wishlist.
>> -Chris
> 
> I added Intel event visualization to gpuvis based on your trace.pl
> script. Screenshot at the top of the wiki page here:
> 
> https://github.com/mikesart/gpuvis/wiki/TechDocs-Intel
> 
> In that screenshot the mouse is hovering over the ctx=30,seqno=1900 bar
> which selects those events in the event list and shows a tooltip with
> the submit, execute, etc info.

It certainly looks immensely better than my browser based hack. But 
unfortunately I still did not get round actually trying your tool.

How scalable it is - meaning - can it handle very busy and huge traces?

Is there any outlook of it getting packaged in some distro?

> For the amdgpu driver, we're able to get the submit information from
> user space and associate those events to specific processes. Example of
> that is here:
> 
> https://github.com/mikesart/gpuvis/wiki/TechDocs-AMDGpu
> 
> If you ever get a chance to try gpuvis and have any feedback, we'd love
> to hear it.  Also if you ever get userspace tracepoint data in, let me
> know and I'd be happy to hook that up as well.

What kind of information is missing to wire up this missing bit? I mean 
the thing you are referring to as user space submit data, what is that?

Btw one new thing we are close to merging to i915 is the perf PMU 
support. That will enable real-time monitoring of per-engine busyness, 
waits, frequency, power, maybe more in the future like queue-depth. I 
don't know if things like that would be interesting for gpuvis? Some of 
it can be inferred from the tracepoints already in post-processing so 
there is some overlap. I am not sure, but thought to mention it. This is 
the series: https://patchwork.freedesktop.org/series/27488/. It is used 
via existing perf userspace API.

Regards,

Tvrtko