[llvm-dev] [cfe-dev] XRay Trace of Clang, Loadable through Chrome Trace Viewer

Fri Dec 15 09:46:16 PST 2017

I believe Trace Compass can read the "Trace event format" natively, but I'll let me colleague comment on this (I forgot to CC the cfe-dev so he could not reply).

Marc-André

________________________________
From: Dean Michael Berris <dean.berris at gmail.com>
Sent: Thursday, December 7, 2017 6:09:09 AM
To: Marc-André Laperle
Cc: Brian Cain; LLVM Developers; Keith Wyss
Subject: Re: [cfe-dev] XRay Trace of Clang, Loadable through Chrome Trace Viewer

Sweet stuff! Thanks for sharing this, Marc-André!

It seems like Trace Compass can already handle CTF. I suspect if we implemented a converter to CTF, that we can turn XRay traces into something that can be visualised with this. That, or have Trace Compass load XRay traces natively.

Cheers

On 7 Dec 2017, at 03:47, Marc-André Laperle <marc-andre.laperle at ericsson.com<mailto:marc-andre.laperle at ericsson.com>> wrote:

"The caveat is, while the tool (llvm-xray convert) can generate arbitrarily large Chrome-loadable traces, the Chrome trace viewer can only handle so much data."

A tool like Trace Compass could help here, it does scale pretty well. (see tracecompass.org<http://tracecompass.org/>)
I'm replying here so a colleague who just suscribed to the mailing list can reply here.

Marc-André

________________________________
From: cfe-dev <cfe-dev-bounces at lists.llvm.org<mailto:cfe-dev-bounces at lists.llvm.org>> on behalf of Dean Michael Berris via cfe-dev <cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>>
Sent: Tuesday, December 5, 2017 3:52 PM
To: Brian Cain
Cc: LLVM Developers; Keith Wyss; Clang Dev
Subject: Re: [cfe-dev] XRay Trace of Clang, Loadable through Chrome Trace Viewer

Sent from my iPhone

On 6 Dec 2017, at 4:17 am, Brian Cain <brian.cain at gmail.com<mailto:brian.cain at gmail.com>> wrote:

On Tue, Dec 5, 2017 at 9:49 AM, Dean Michael Berris via cfe-dev <cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>> wrote:
Hi cfe-dev@ and llvm-dev@,

I've attached a Chrome trace-viewer readable trace of a clang built with XRay instrumentation (additional build/link flags="-fxray-instrument -fxray-instruction-threshold=75") with the latest "top-of-trunk" version of clang with the recent updates to the XRay runtime supporting record filtering.

To load the attached file, go to 'chrome://tracing' in your Chrome/Chromium browser and load the .gz file directly. Pressing '?' should give a help dialog.

This is an interesting feature.  Is it designed to accept arbitrary xray trace logs or only ones for/from Chrome/ium?

Yes, it works on any XRay trace generated with the logging implementations that come with XRay in compiler-rt.

The example attached was of an instrumented Clang binary compiling C++ code. 😁

The caveat is, while the tool (llvm-xray convert) can generate arbitrarily large Chrome-loadable traces, the Chrome trace viewer can only handle so much data.

Cheers

-- Dean

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