1111948 - Fix --disable-startupcache, and re-disable the startup cache on B2G in the process

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Nicholas Nethercote [inactive]]

Bug 988880 disabled the startup cache on B2G, because it's not useful and takes up memory. It landed in April.

Just one week later, bug 999631 tweaked the mechanism used to disable the startup cache by adding --disable-startupcache. But this option has two defects.

- There's no AC_DEFINE(MOZ_DISABLE_STARTUPCACHE).

- Even if there was, the relevant #ifdef uses MOZ_DISABLE_STARTUP_CACHE, which has an extra '_' and so will never match.

This means that the startup cache is always enabled.

Pro-tip: when you add a new configuration option, test that the non-default option works before you land it.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: Fix --disable-startupcache, and re-disable the startup cache on B2G in the process

Comment 2

[Nicholas Nethercote [inactive]]

I tested this in the following configurations:

- Desktop, normal: startup cache is enabled
- Desktop, with --disable-startupcache: startup cache is disabled
- B2G: startup cache is disabled

Comment 3

[Alexandre Poirot [:ochameau]]

Oops, sorry about that. It is frightening to see that we can regress memory usage so badly without any report :/

Comment 4

[Michael Shal [:mshal]]

Comment on attachment 8536954 [details] [diff] [review]
Fix --disable-startupcache, and re-disable the startup cache on B2G in the process

Sorry, I should have caught that in review.

Comment 5

[Bobby Holley (:bholley)]

Bug 989373 indicates that this has a very big impact on builds with de-merged compartments. What is the memory impact of this bug on the devices we ship?

Comment 6

[Nicholas Nethercote [inactive]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/cbe11e6e68f1

Comment 7

[Nicholas Nethercote [inactive]]

> What is the memory impact of this bug on the devices we ship?

With system compartment merging on, the startup cache took up 180 KiB for the two runs I did yesterday on my Buri.

Comment 8

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/cbe11e6e68f1