Closed Bug 609296 Opened 14 years ago Closed 11 years ago

Number.toString() is slow

Categories

(Core :: JavaScript Engine, defect)

defect
Not set
normal

Tracking

()

RESOLVED FIXED
mozilla28
Tracking Status
firefox28 --- fixed

People

(Reporter: jandem, Assigned: jandem)

References

(Blocks 3 open bugs)

Details

Attachments

(1 file, 1 obsolete file)

Peacekeeper's SHA1 benchmark calls Number.prototype.toString 2.000.000 times, this is 3x slower in JM than in V8. Pics output tells us why: "callprop disabled: non-string primitive" I think CALLPROP needs a generateNumberCallStub based on generateStringCallStub? Or a generic generatePrimitiveCallStub that handles both strings and numbers. For this benchmark: ---- function test(x) { var t0 = new Date; var s; for(var i=0; i<2000000; i++) { s = (x|0).toString(); } print(new Date - t0); } test(10); ---- I get these numbers: -j: 28 ms v8: 52 ms -m: 147 ms So we can win at least 70 ms (5-8%) on this Peacekeeper benchmark (JM-only, don't know about JM+TM).
Blocks: 609212
No longer blocks: peacekeeper
What's TM doing right here, and can JM just do that? ;)
(In reply to comment #1) > What's TM doing right here, and can JM just do that? ;) IIUC TM calls js_NumberToString{WithBase} directly (jsnum.cpp). JM calls num_toString, which does GetPrimitiveThis and then also calls NumberToStringWithBase. Maybe JM can do what TM does by special-casing num_toString.
Now that primitive wrapping is gone, we should be able to generate normal ICs here, like we do for strings.
Assignee: general → jandemooij
Status: NEW → ASSIGNED
Attached patch WIP v1 (obsolete) (deleted) — Splinter Review
This makes the callprop string path more generic so we can use it for numbers and booleans. Some numbers: Peacekeeper SHA1: -m: before: 1714 ms after: 1623 ms -m -j -p: before: 1539 ms after: 1451 ms Micro-bench, comment 0, -m: before: 145 ms after: 81 ms If I add this line: Number.prototype.toString = function() { return 0; } -m (before) 94 ms -m (after): 18 ms -j: 318 ms V8: 4452 ms This also wins 5 ms on v8 earley-boyer and 1-2 ms on SS unpack-code. This passes tests but I still need to do some cleanup and write tests.
Current js shell numbers for the comment #0 testcase: Interp: 270 JM: 143 JM+TI: 130 d8: 37 jandem, is this still on your radar?
Blocks: 467263
(In reply to Ryan VanderMeulen from comment #5) > jandem, is this still on your radar? I'm not going to work on this, but a contributor may be interested. With TI, it should be much easier to add a fast path.
Assignee: jdemooij → general
Status: ASSIGNED → NEW
Apparently, we got worse at this with IM: Current js shell numbers for the comment #0 testcase: Interp: 446 Baseline: 266 IM: 161 d8: 25 I wonder why Interp regressed this much. (Assuming we did, but I can't believe that my machine is that much slower than jandem's from 1.5 years ago *and* v8 got that huge a speed boost.)
Summary: JM: number.toString() is slow → Number.toString() is slow
v8 has an inline stub in crankshaft that looks up the cached string representation for numbers.
Blocks: 626165
Attached patch Patch (deleted) — Splinter Review
Baseline has a stub for GETPROP on strings. This patch makes that stub work on numbers and booleans as well. It also fixes IonBuilder so that it optimizes the number.toString singleton access. Improves the testcase in comment 0 from 217 to 35 ms and seems to win a few ms on SS unpack-code.
Assignee: general → jdemooij
Status: NEW → ASSIGNED
Attachment #8339282 - Flags: review?(bhackett1024)
Attachment #495537 - Attachment is obsolete: true
Comment on attachment 8339282 [details] [diff] [review] Patch Review of attachment 8339282 [details] [diff] [review]: ----------------------------------------------------------------- ::: js/src/jit/BaselineIC.cpp @@ +6183,5 @@ > if (IsIonEnabled(cx)) > + types::EnsureTrackPropertyTypes(cx, proto, id); > + > + // For now, only look for properties directly set on the prototype. > + RootedShape shape(cx, proto->nativeLookupPure(id)); This can use nativeLookup instead.
Attachment #8339282 - Flags: review?(bhackett1024) → review+
Status: ASSIGNED → RESOLVED
Closed: 11 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla28
Flags: in-testsuite?
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