844284 - (b2g-valgrind) Tracking: Make it easy to run valgrind on b2g

Status: RESOLVED FIXED

(Firefox OS Graveyard :: General, defect, P3)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Running valgrind on low-end devices has been a pipe dream rarely dreamt, but apparently bent got this running on (full RAM) unagi!

This bug intends to track the work we need to
 - get the vg hacks upstreamed
 - include valgrind sources or prebuilt binary in b2g repo manifests
 - add easy helpers for developers to launch this on real HW, like the helpers we have for loading the profiler

Doing stability and unit testing runs under valgrind is really the holy grail of testing.

Comment 1

[Julian Seward [:jseward]]

> apparently bent got this running on (full RAM) unagi!

Cool.

> This bug intends to track the work we need to
>  - get the vg hacks upstreamed

Not sure what you mean by this (upstream V or upstream in b2g world?)
and which hacks?  unwind/mem reduction hacks for V that I sent to
bent, or something else?

Some easy wins for V/B2G are

* reduce size of V's translation cache from default; saves 20-40MB.
  Could do this automatically when built for Android/B2G.

* debuginfo reading/storage improvements; saves 10ish MB for libxul.
  I have a prototype patch but needs reworking.

* Replace some hot C code fragments in V with handcoded assembly.
  With a bit of luck might be able to crank another 10% performance
  out of V/Memcheck on ARM.  See
  https://bugs.kde.org/show_bug.cgi?id=314365#c2 and c6

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

(In reply to Julian Seward from comment #1)
> > This bug intends to track the work we need to
> >  - get the vg hacks upstreamed
> 
> Not sure what you mean by this (upstream V or upstream in b2g world?)

Upstream V.  We don't want to sit on a fork.

> and which hacks?  unwind/mem reduction hacks for V that I sent to
> bent, or something else?

Yup.

Comment 3

[Kyle Machulis [:qdot] [:kmachulis] (INACTIVE)]

Documentation is up (https://developer.mozilla.org/en-US/Firefox_OS/Debugging/Debugging_B2G_using_valgrind), valgrind is working well (filed a bunch of stuff last night). Calling this done.