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{ Category Archives } Program Execution

Visualizing Program Execution

about:nosy can now show CPU usage using jsprobes

Refresher: about:nosy was introduced one week ago as a way to see the memory usage of your tabs and extensions (that live in compartments).  It sorta looked like this: Except those (green) bars on the right are new.  The ones on the left, they show memory.  The ones on the right, they show CPU usage.  […]

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about:nosy is about:memory with charts, helps you lay blame more easily

about:memory and the memory reporter infrastructure that powers it are amazing.  They provide an explicit hierarchy that breaks down the memory use in the system to the subsystems and increasingly the causes of allocation.  about:memory looks like this (if you stand a few feet back from your monitor and take off your glasses): If you […]

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The joy of integrated logging and log viewing with fancy logs

The deuxdrop messaging experiment‘s current incarnation exists as an (under development) Jetpack that runs in Firefox.  I am still trying to shake out functionality to be driven by the UI rather than headless unit tests.  While firebug has been a great help, another boon has been the logging framework and log viewing framework developed for […]

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overview ownership/communication graphs for rich execution logs

My last blog post covered the fancy pants logging being used for the deuxdrop project.  To summarize: we have loggers they are organized by ownership hierarchy they provide sufficient metadata that we can reconstruct the loggers that were talking to each other This can result in a lot of loggers.  If you look at the […]

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new adventures in rich (execution) logs for debugging and program understanding

Understanding what is going on inside software can be very hard, even for the developers most familiar with the software.  During my time working on Thunderbird I used a variety of techniques to try and peer inside: printf/dump/console.log, debuggers, execution analysis (dtrace, chronicle recorder, with object diffs, on timelines), logging (log4j style, with  timelines, with […]

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logsploder, circa a year+ ago

Whoops.  I posted to mozilla.dev.apps.thunderbird about an updated version of logsploder at the end of 2009, but forgot to blog about it.  I do so now (briefly) for my own retrospective interest and those who like cropped screenshots. The gloda (global database) tests and various Thunderbird mozmill tests have been augmented for some time (1+ […]

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Visualizing asynchronous JavaScript promises (Q-style Promises/B)

Asynchronous JS can be unwieldy and confusing.  Specifically, callbacks can be unwieldy, especially when you introduce error handling and start chaining asynchronous operations.  So, people frequently turn to something like Python’s Twisted‘s deferreds which provide for explicit error handling and the ability for ‘callbacks’ to return yet another asynchronous operation. In CommonJS-land, there are proposals […]

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wmsy’s debug UI’s decision tree visualizer

wmsy, the Widget Manifesting SYstem, figures out what widget to display by having widgets specify the constraints for situations in which they are applicable.  (Yes, this is an outgrowth of an earlier life involving multiple dispatch.)  Code that wants to bind an object into a widget provides the static, unchanging context/constraints at definition time and […]

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fighting oranges with systemtap probes, latency fighting; step 2

Recap from step 1: Sometimes unit test failures on the mozilla tinderboxen are (allegedly, per me) due to insufficiently constrained asynchronous processes.  Sometimes the tests time out because of the asynchronous ordering thing, sometimes it’s just because they’re slow.  Systemtap is awesome.  Using systemtap we can get exciting debug output in JSON form which we […]

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fighting non-deterministic xpcshell unit tests through causality tracking with systemtap; step 1

It’s a story as old as time itself.  You write a unit test.  It works for you.  But the evil spirits in the tinderboxes cause the test to fail.  The trick is knowing that evil spirits are a lot like genies.  When you ask for a wish, genies will try and screw you over by […]

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