666340 - Serialize the memory cache on shutdown

Status: RESOLVED WONTFIX

(Firefox for Android Graveyard :: General, defect)

Description

[Chris Lord [:cwiiis]]

User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:7.0a1) Gecko/20110622 Firefox/7.0a1
Build Identifier: 

We can probably reduce page-load time and bandwidth use slightly if we serialize the memory cache on shut-down, and deserialize it on startup. This ought to help with restart speed to, when restoring tabs.

This may work quite nicely in addition to a disk cache (bug #645848).

Reproducible: Always

Comment 1

[Chris Lord [:cwiiis]]

Attachment: Serialize the memory cache to disk

This patch serializes the memory cache on memory-pressure and on shutdown, and deserializes when initialising the session store (which happens before restoring the session).

Probably not really ready for review yet.

Comment 2

[Chris Lord [:cwiiis]]

Just a note, this doesn't seem hugely effective unless you increase the memory cache size (browser.cache.memory.capacity) - I find 4 megs seems to give more reasonable results (the default is 1).

Perhaps we could have a more intelligent eviction algorithm? (I notice in my cache that a lot of ads and ad-related content gets cached vs. main page resources)

Comment 3

[Geoff Brown [:gbrown]]

(In reply to comment #2)
> Perhaps we could have a more intelligent eviction algorithm? (I notice in my
> cache that a lot of ads and ad-related content gets cached vs. main page
> resources)

Be aware of bug 661900 -- this *might* be contributing to your eviction problem.

Comment 4

[Chris Lord [:cwiiis]]

Attachment: Part 1 - Serialize memory cache on session close/memory-pressure, deserialize on new session

Updated patch.

This version also uses the browser.cache.check_doc_frequency pref when restoring the last session to (hopefully) stop from verifying cache entries. The pref is reset once the page has finished loading or is stopped.

Not sure if this is a good idea or not, ideally there'd be a way to do what this pref does on a per-tab basis.

Comment 5

[Chris Lord [:cwiiis]]

Attachment: Part 2 - Add session-restore option

This patch adds an extra startup option that allows you to restore the last session. Probably not that desirable on a phone perhaps, but I like this option on a tablet.

Comment 6

[Chris Lord [:cwiiis]]

Attachment: Part 3 - Add compatibility with bug

Comment 7

[Chris Lord [:cwiiis]]

Attachment: Part 3 - Add compatibility with bug #648429

This patch tweaks the serialization slightly to take advantage of the cache compression provided in bug #648429.

Comment 8

[Chris Lord [:cwiiis]]

Attachment: Part 2 - Add session-restore option (fixed)

Whoops, the optional session restore didn't work because the preference wasn't added by default.

Comment 9

[Chris Lord [:cwiiis]]

Just to note, it's only the first hunk of that patch that's relevant to this, you could just apply that and ignore the rest.

Comment 10

[Chris Lord [:cwiiis]]

ugh, ignore last comment, wrong bug.

Comment 11

[Chris Lord [:cwiiis]]

Just checking back on this, is memory cache serialization something we want? Our default memory cache size is only 1meg, so it barely helps in that situation, but coupled with an increased size of 4 megs and perhaps memory cache compression, you might be looking at saving some precious bandwidth.

It has no considerable effect on loading times, as far as I can see, in practical situations at least, so I think this should be considered purely on its saving-bandwidth potential (at the expense of storage space).

I think this would also be superseded by the work on getting disk cache usable on mobile too.

Thoughts?

Comment 12

[Chris Lord [:cwiiis]]

I don't think I'm the right person to be dealing with this, unassigning.

Comment 13

[BMO Automation]

Closing all opened bug in a graveyard component