Last Comment Bug 748444 - eliminate relocations required by gHistograms
: eliminate relocations required by gHistograms
Product: Toolkit
Classification: Components
Component: Telemetry (show other bugs)
: unspecified
: All All
-- normal (vote)
: mozilla18
Assigned To: Nathan Froyd [:froydnj]
: Georg Fritzsche [:gfritzsche]
Depends on: 748417
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Reported: 2012-04-24 10:46 PDT by Nathan Froyd [:froydnj]
Modified: 2012-08-30 03:54 PDT (History)
1 user (show)
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patch (6.77 KB, patch)
2012-08-29 08:59 PDT, Nathan Froyd [:froydnj]
taras.mozilla: review+
Details | Diff | Splinter Review

Description User image Nathan Froyd [:froydnj] 2012-04-24 10:46:13 PDT
bug 748417 is going to write a python script to parse TelemetryHistograms.h.  Once that's written, we should use the script to generate gHistograms at compile time; doing that will enable eliminating the pointers to names and descriptions (can simply use indices into a global char[] instead), reducing relocations and footprint.
Comment 1 User image Nathan Froyd [:froydnj] 2012-08-29 08:59:00 PDT
Created attachment 656475 [details] [diff] [review]

I realize StringTable is a little overkill, but I copied the code directly from quickstubs, so I know it works, and if we start annotating histograms with units, we'll need something like StringTable anyway.  So I'd like to keep it around.
Comment 2 User image (dormant account) 2012-08-29 10:07:39 PDT
Comment on attachment 656475 [details] [diff] [review]

Comment 3 User image (dormant account) 2012-08-29 10:08:22 PDT
What are the footprint wins here?
Comment 4 User image Nathan Froyd [:froydnj] 2012-08-29 10:18:11 PDT
(In reply to Taras Glek (:taras) from comment #3)
> What are the footprint wins here?

N histograms * (2 relocations + 1 word).  More than 1k bytes, less than 10k bytes on x86/ARM Linux.  Might be the same range for x86-64/Linux.  I imagine it's roughly the same on Windows and OS X, but not really sure.
Comment 6 User image Ed Morley [:emorley] 2012-08-30 03:54:56 PDT

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