104170 - FastLoad file contains many redundant (sub)strings

Status: NEW

(Core :: XPCOM, defect, P3)

Description

[Brendan Eich [:brendan]]

JS atoms are flattened (this is really a JS XDR bug/misfeature) into strings as
they are serialized.  URI specs and file pathnames are not compressed if
relative to an earlier base.  Etc.

/be

Comment 1

[Brendan Eich [:brendan]]

Following bug 107907 to 0.9.7.

/be

Comment 2

[Brendan Eich [:brendan]]

Design note to self: JS XDR is a lower below the object/binary stream
implemented by nsFastLoadFile{Reader,Writer}.  Both layers want a dictionary of
shared strings (for strings long enough to be worth sharing).  A new interface,
nsIFastLoadStringTable (or perhaps a more generic name), should be implemented
and used by nsFastLoadFileWriter::WriteString, etc.

/be 

Comment 3

[Brendan Eich [:brendan]]

This one is following bug 107907 to 0.9.8.

/be

Comment 4

[Brendan Eich [:brendan]]

Still want this for 1.0, which means 0.9.9 or bust.

/be

Comment 5

[Brendan Eich [:brendan]]

Bust.  This is not vital for 1.0 unless someone can show a big startup perf gain
over what FastLoad currently gives.  The file (not RAM, except for the extra
i/o) footprint doesn't matter enough to rush this in.

/be

Comment 6

[Brendan Eich [:brendan]]

I'm an optimist.

/be

Comment 7

[Brendan Eich [:brendan]]

This is 1.2alpha material, not 1.1beta.

/be

Comment 8

[Brendan Eich [:brendan]]

Moving out, some of these may move to 1.3alpha shortly.

/be

Comment 9

[Brendan Eich [:brendan]]

Fixing TM.

/be

Comment 10

[(dormant account)]

This should be a feature in the rewamped startup cache.

Comment 11

[Brendan Eich [:brendan]]

Comment 10 and the dependency on bug 520309 say that this bug must wait, but see bug 517956 comment 2 for reference to bz's specific script->filename issue, which could be fixed ad-hoc.

/be

Comment 12

[Brendan Eich [:brendan]]

Ben, feel free to steal or dup.

/be

Comment 13

[Michael Wu [:mwu]]

I guess this is a sort of metabug now?

I have patches in bug 518230 and bug 632253 which reduce the size of serialized scripts a bunch. XPIProvider.jsm is 40% smaller with those patches. However, the serialized js is still bigger than the original js when compressed.

Comment 14

[Benjamin Smedberg]

Is this a problem specific to XDR? Does this even still exist with s/fastload/startupcache/?

Comment 15

[(dormant account)]

(In reply to Benjamin Smedberg  [:bsmedberg] from comment #14)
> Is this a problem specific to XDR? Does this even still exist with
> s/fastload/startupcache/?

yes see comment 13