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{ Category Archives } Program Execution

Visualizing Program Execution

work-in-progress tooling: feeding GWT SpeedTracer systemtapped mozilla performance data

Now that Thunderbird 3.1 is string/feature-frozen it’s time to focus on performance.  This post is just to make sure that people who are also working on similar things know what I’m up to.  For example, there’s some very exciting work going on involving adding a startup timeline to mozilla-central that everyone keeping up-to-date with mozilla […]

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a systemtap script to attribute JS string memory costs to the creating JS functions

—– js_GC data pages: 96731 total vm pages: 234849 ### KiB 11376 839 BF_format log4moz.j:487 15906 725 mime_emitter_writeBody jsmimeemitter.j:381 148 576 MimeMessage_coerceBodyToPlaintext mimemsg.j:341 4460 492 gloda_ds_queryFromQuery datastore.j:2988 9655 387 <MYSTERIOUS> <BEYOND THE VEIL>:0 911 237 gloda_content_quoted connotent.j:267 1723 144 gloda_indexMessage index_msg.j:2597 187 141 gloda_content_content connotent.j:290 170 108 gloda_content_getContent connotent.j:166 1917 73 gloda_identity_toString datamodel.j:785 1775 69 […]

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performance annotated SQLite EXPLAINation visualizations using systemtap

For the Thunderbird 3.1 release cycle we are not just fixing UX problems but also resolving various performance issues.  The key to defeating performance problems, like the key to defeating bad guys in movies, is to make sure they are dead.  If you want to fight the bad guy again, you can just assume that […]

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Using VMWare Record/Replay and VProbes for low time-distortion performance profiling

The greatest problem with performance profiling is getting as much information as possible while affecting the results as little as possible.  For my work on pecobro I used mozilla’s JavaScript DTrace probes.  Because the probes are limited to notifications of all function invocations/returns with no discretion and there is no support for JS backtraces, the […]

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displaying execution traces on a SIMILE timeline

chroniquery can now output JSON for display using the SIMILE timeline widget.  And I am finally done trying to figure out what was going wrong.  Click the pictures to experience the timeline sensation for yourself. Related interesting things: Supports a fancy if specific constraint mechanism.  For example, PrepareAndDispatch is only displayed in the context of […]

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understanding where unit tests go wrong with object diffs

In our last chroniquery adventure, we used roc‘s chronicle-recorder to trace the execution of an xpcshell unit test and chroniquery (repo info) to use that trace to help us understand what was happening in some particularly confusing C-ish code.  Actually, we’re doing that this time too, but the bag of tricks now contains additional tricks. […]

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understanding libmime using chroniquery and unit tests

Mailnews’ libmime is one of the harder modules to wrap one’s head around.  8-letter filenames where the first four letters tend to be “mime”, home-grown glib-style OO rather than actual C++, and intermingling of display logic with parsing logic do not make for a fun development or even comprehension experience. Running an xpcshell unit test […]

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visualization of control-flow/data-flow analysis of sqlite EXPLAIN-ations

While doing some work on the gloda-based search targeted for beta 2, I came upon some query slowness and decided to look into it.  Because gloda queries are (conceptually, at least) dynamic, we also generate dynamic SQL.  Our schema is fairly normalized, and it’s not always obvious to me what I can expect to have […]

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LogSploder, logsploding its way to your logs soon! also, logsplosion!

In our last logging adventure, we hooked Log4Moz up to Chainsaw.  As great as Chainsaw is, it did not meet all of my needs, least of all easy redistribution.  So I present another project in a long line of fantastically named projects… LogSploder! The general setup is this: log4moz with a concept of “contexts”, a […]

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chroniquery does useful things!

Before pecobro, there was chroniquery (shiny, also shiny, texty), a python binding for roc‘s chronicle-recorder omega-debugger.  Now, there is still chroniquery.  It just does more stuff, and does the stuff it previously did more correctly. In any event, what the awesome ‘screenshot’ (it’s from a console…) shows: A trace from running chronicle-recorder against xpcshell on […]

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