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RE: Proposal for JavaScript Timing Extension to the Performance Timeline

From: Alois Reitbauer <alois.reitbauer@dynatrace.com>
Date: Thu, 16 Feb 2012 10:28:12 +0000
To: Nat Duca <nduca@google.com>
CC: Boris Zbarsky <bzbarsky@mit.edu>, "public-web-perf@w3.org" <public-web-perf@w3.org>
Message-ID: <A8638EB8DF9DE24D8C1E12D326D97AC399B98B@ATEX01.dynatrace.local>
I do not see a relationship between these two. This is about getting actual JavaScript timings via the Performance Timeline while the other one reports back the current time in the browser.

// Alois

From: Nat Duca [mailto:nduca@google.com]
Sent: Thursday, February 16, 2012 8:02 AM
To: Alois Reitbauer
Cc: Boris Zbarsky; public-web-perf@w3.org
Subject: Re: Proposal for JavaScript Timing Extension to the Performance Timeline

How does this relate to window.performance.now() that was discussed previously?

On Wed, Feb 15, 2012 at 8:30 AM, Alois Reitbauer <alois.reitbauer@dynatrace.com<mailto:alois.reitbauer@dynatrace.com>> wrote:
The idea is to get the first executing function. This should be enough information for monitoring. If even this information cannot be provided at least a performance Entry object with an empty name should be created.

// Alois

-----Original Message-----
From: Boris Zbarsky [mailto:bzbarsky@MIT.EDU<mailto:bzbarsky@MIT.EDU>]
Sent: Wednesday, February 15, 2012 5:16 PM
To: public-web-perf@w3.org<mailto:public-web-perf@w3.org>
Subject: Re: Proposal for JavaScript Timing Extension to the Performance Timeline

On 2/15/12 5:03 AM, Alois Reitbauer wrote:
> A while ago, I submitted a list of potential future work targeted at
> getting more insight into the runtime behavior of JavaScript heavy web
> applications. As a first result out of these initial ideas I came up
> with a proposal how to extend the Performance Timeline to expose
> JavaScript execution time information.
> As formatting is limited for mailing list messages I posted a
> formatted and easy to read version of the proposal at
> http://blog.dynatrace.com/2012/02/15/specification-proposal-for-javasc
> ript-timing-in-browsers/
> Please provide feedback.

When this feature is enabled, what should be reported for function execution times in a JIT compiler which inlines functions and then does common subexpression elimination and constant-folding on the resulting code, effectively across function boundaries?

Of course one could disable such optimizations when the timeline is on, but that would materially change the performance characteristics of the script in the cases of interest....

Received on Thursday, 16 February 2012 10:28:51 UTC

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