815579 - IonMonkey: Compile function called through VM call Invoke faster.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Hannes Verschore [:h4writer]]

Calling from IM to Interpreter/JM through a VM call is slow. We should consider compiling that function earlier in order to use a fastcall from MI -> MI. ATM we use usecount to determine this, but we could cheat and increase usecount faster when a function is called through VM call. This makes sense because:

V8 compile times:
mean	272us
ssd	317us
max	2952us
min	14us

SS compile times:
mean	364us
std	457us
max	2482us
min	22us

Overhead VM call (no execution time is taken in account. Only the transition from IM to Interpreter):
mean    2us
max     3us
min     1us

So calling this function 10.240 times through VM call would yield an overhead of 20480. This is 10x higher than the max. compile time of V8/SS on a function. Therefore it would be smart to increase (pessimistic) with "10" every time we call through invoke. We could even (optimistic) increase with "100" and our mean compile time is payed by not using the VM call.

This would give an increase of 6%-8% on v8-raytrace, because e.g. (but not only) raytrace.js:426 now gets compiled and has the benefit of running using IM to IM calls.

I'll give the patch and numbers on Kraken, SS and V8 this afternoon.

Comment 1

[Hannes Verschore [:h4writer]]

Sunspider:

3d-raytrace:
 1308 => 1000 InvokeFunction
 22.4ms +/- 4.7%    22.1ms +/- 5.4%

string-validate-input:
  786 =>  324 InvokeFunction
 9.4ms +/- 4.8%     9.0ms +/- 3.6%

other tests in SS don't use InvokeFunction and are unaffected

V8:

Richards
  18.194 to   4.551 InvokeFunction
    7430 to    7268 (before patch, jumping between 7000 and 7500, after patch consistent 7250)
DeltaBlue
 341.900 to  89.506 InvokeFunction
    8360 to    8162
Crypto
 119.343 to 203.541 InvokeFunction
   10539 to   10811
RayTrace
 137.079 to  32.097 InvokeFunction
    5432 to    5755
EarleyBoyer
 455.202 to 121.823 InvokeFunction
    9625 to   10056
RegExp
       0 to       0 InvokeFunction
    1183 to    1192
Splay
  59.304 to  11.114 InvokeFunction
    8160 to    8418
NavierStokes
     460 to     490 InvokeFunction
   15744 to   15567
Total:
    6906 to    6998

Raytrace, EarleyBoyer, Splay show a nice speedup. 
Richards and Deltablue decrease performance
Overal speedup of 1%-2%

Kraken:

===============================================
RESULTS (means and 95% confidence intervals)
-----------------------------------------------
Total:                       2523.7ms +/- 2.0%
-----------------------------------------------

  ai:                         145.1ms +/- 0.9%
    astar:                    145.1ms +/- 0.9%

  audio:                      924.5ms +/- 5.3%
    beat-detection:           297.0ms +/- 12.4%
    dft:                      225.5ms +/- 0.8%
    fft:                      182.7ms +/- 19.7%
    oscillator:               219.3ms +/- 0.7%

  imaging:                    671.3ms +/- 4.4%
    gaussian-blur:            272.2ms +/- 9.2%
    darkroom:                 226.3ms +/- 0.8%
    desaturate:               172.8ms +/- 11.3%

  json:                       142.5ms +/- 1.2%
    parse-financial:           91.0ms +/- 1.2%
    stringify-tinderbox:       51.5ms +/- 2.8%

  stanford:                   640.3ms +/- 0.5%
    crypto-aes:               142.7ms +/- 1.2%
    crypto-ccm:               143.6ms +/- 1.0%
    crypto-pbkdf2:            258.8ms +/- 0.9%
    crypto-sha256-iterative:   95.2ms +/- 0.5%

to 

===============================================
RESULTS (means and 95% confidence intervals)
-----------------------------------------------
Total:                       2499.9ms +/- 1.9%
-----------------------------------------------

  ai:                         144.9ms +/- 0.4%
    astar:                    144.9ms +/- 0.4%

  audio:                      912.1ms +/- 4.1%
    beat-detection:           281.3ms +/- 0.7%
    dft:                      244.5ms +/- 15.1%
    fft:                      166.0ms +/- 0.5%
    oscillator:               220.3ms +/- 0.9%

  imaging:                    656.3ms +/- 1.7%
    gaussian-blur:            261.7ms +/- 0.7%
    darkroom:                 226.7ms +/- 1.0%
    desaturate:               167.9ms +/- 5.9%

  json:                       151.3ms +/- 13.8%
    parse-financial:          100.1ms +/- 20.6%
    stringify-tinderbox:       51.2ms +/- 3.5%

  stanford:                   635.3ms +/- 5.0%
    crypto-aes:               141.9ms +/- 1.7%
    crypto-ccm:               136.4ms +/- 1.4%
    crypto-pbkdf2:            255.5ms +/- 7.0%
    crypto-sha256-iterative:  101.5ms +/- 14.3%

Comment 2

[Hannes Verschore [:h4writer]]

Attachment: Increment usecount on slow call

This increases the use count when calling invoke with 5. (The tests above are done with 10). Decreasing to 5 yields the same performance increase on v8-raytrace, but doesn't decrease performance on v8-richards.

Comment 3

[Hannes Verschore [:h4writer]]

Comment on attachment 685610 [details] [diff] [review]
Increment usecount on slow call

Review of attachment 685610 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/ion/VMFunctions.cpp
@@ +71,5 @@
>  
> +    // When caller runs in IM, but callee not, we take a slow path to the interpreter.
> +    // This has a significant overhead. In order to decrease the number of times this happens,
> +    // the useCount gets incremented faster to compile this function in IM and use the fastpath.
> +    fun->nonLazyScript()->incUseCount(js_IonOptions.slowCallIncUsecount);

The "C" of slowCallIncUsecount should be capitalized. (Probably forget to qref before posting)

Comment 4

[Hannes Verschore [:h4writer]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/bc06441af87e

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/bc06441af87e