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  1. 01 Apr, 2019 3 commits
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  11. 25 Mar, 2019 3 commits
    • Mythri's avatar
      [lite] Allocate feedback vectors lazily · 7629afdb
      Mythri authored 
      Allocate feedback vectors lazily when the function's interrupt budget has
reached a specified threshold. This cl introduces a new field in the
ClosureFeedbackCellArray to track the interrupt budget for allocating
feedback vectors. Using the interrupt budget on the bytecode array could
cause problems when there are closures across native contexts and we may
delay allocating feedback vectors in one of them causing unexpected
performance cliffs. In the long term we may want to remove interrupt budget
from bytecode array and use context specific budget for tiering up decisions
as well.

Bug: v8:8394
Change-Id: Ia8fbb71f5e8543a92f14c44aa762973da82d445c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1520719
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: 's avatarJaroslav Sevcik <jarin@chromium.org>
Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
Reviewed-by: 's avatarRoss McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60450}
      7629afdb
    • Igor Sheludko's avatar
      [classes] Properly handle static length computed property · 26ffe82e
      Igor Sheludko authored 
      Bug: chromium:913943
Change-Id: I2f7774ca1ea0a7855620a99d7e26cd764260129b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1538124
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: 's avatarToon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60449}
      26ffe82e
    • Benedikt Meurer's avatar
      [tracing] Improve tracing signals for compilation/optimization. · a2af7e11
      Benedikt Meurer authored 
      This adds OBJECT/SNAPSHOT trace events for Script and SharedFunctionInfo
objects, logging their creation with appropriate information to make
sense of them.

Based on that we introduces five flow events to model the optimized
compilation via tracing in the "disabled-by-default-v8.compile" category:

  - "v8.optimizingCompile.start" logs the creation of the
    PipelineCompilationJob (for TurboFan JavaScript optimization)
    with the "function" argument referring to the trace event
    object created for the SharedFunctionInfo.
  - "v8.optimzingCompile.prepare" logs the preparation of the
    PipelineCompilationJob on the main thread, also carrying the
    "function" argument. This connects the flow event to the actual
    tracing duration event associated with the preparation phases.
  - "v8.optimizingCompile.execute" logs the (usually concurrent)
    optimization of the TurboFan graph (again with "function").
  - "v8.optimizingCompile.finalize" logs the main thread phase which
    finalizes the optimized code and eventually installs it (in case
    of success).
  - "v8.optimizingCompile.end" signals the end of the
    PipelineCompilationJob, which carries the "compilationInfo",
    that contains the interesting bits of the OptimizedCompilationInfo,
    specifically whether the compile was successfull and which functions
    were inlined for example.

This also adds two instant events "V8.AbortOptimization" and
"V8.RetryOptimization" in "disabled-by-default-v8.compile" category
that are emitted when TurboFan cannot optimize a certain function.
In case of "V8.RetryOptimization", TurboFan might be able to optimize
it later, whereas "V8.AbortOptimization" permanently disables the
optimization of a given function. The JSON representation of this is

```js
{
  "pid": 256639,
  "tid": 256639,
  "ts": 6935411377801,
  "tts": 159116,
  "ph": "I",
  "cat": "disabled-by-default-v8.compile",
  "name": "V8.AbortOptimization",
  "dur": 0,
  "tdur": 0,
  "args": {
    "reason": "Function is too big to be optimized",
    "function": {
      "id_ref": "0x600000001",
      "scope": "v8::internal::SharedFunctionInfo"
    }
  }
},
```

where the "function" refers to a previously emitted SNAPSHOT for the
function in question. In the trace viewer it will show up as instant
event under "v8.optimizingCompile.prepare" in case of the relevant
example where optimization is disabled due to reaching the bytecode
limit (as in the JSON above), i.e. it'll look something like this

  https://i.paste.pics/aafc2de9df10ea8f5acc1a761d80f07b.png

for the example highlighted in the recent blog post

  https://ponyfoo.com/articles/javascript-performance-pitfalls-v8

that describes the optimization limit. The "v8.optimizingCompile.end"
duration event will also carry this information as part of the
"compilationInfo" object, but specifically for CI tools, etc. it might
be a whole lot easier to just look for the "V8.AbortOptimization"
instant event.

Bug: v8:8598, v8:9039
Tbr: ulan@chromium.org
Doc: bit.ly/v8-tracing-signals
Change-Id: Ic87ac336004690c65b6b15ad73bc6fbd4b5f12c4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1511483
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: 's avatarPeter Marshall <petermarshall@chromium.org>
Reviewed-by: 's avatarBenedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60448}
      a2af7e11