StringDictionarySlim instead of Dictionary/StructDictionary #554
Conversation
lahma
changed the title
…tDictionary * remove intrinsic properties
lahma
force-pushed
the
perf/DictionarySlim
branch
from
131695c
to
4531ced
Compare
lahma
changed the title
| @@ -18,8 +19,7 @@ namespace Jint.Native.Object | |||
| { | |||
| public class ObjectInstance : JsValue, IEquatable<ObjectInstance> | |||
| { | |||
| protected Dictionary<string, PropertyDescriptor> _intrinsicProperties; | |||
| protected internal Dictionary<string, PropertyDescriptor> _properties; | |||
| internal StringDictionarySlim<PropertyDescriptor> _properties; | |||
There was a problem hiding this comment.
Why a single dictionary now? Didn't I do two dictionaries on purpose?
There was a problem hiding this comment.
Well I couldn't find the reason to have separate _intrinsicProperties, tried to read the ECMA spec and it doesn't have such distinction. Symbolic properties work the same way as normal properties etc.
There was a problem hiding this comment.
I think it might be for iterating. Pretty sure it was necessary.
There was a problem hiding this comment.
Let's see how it goes without it then, next time I think something matters I'll write a unit test ;)
| _properties?.Clear(); | ||
| _intrinsicProperties?.Clear(); | ||
|
|
||
| _properties = null; |
There was a problem hiding this comment.
Wasn't the goal here to reuse the same instance?
There was a problem hiding this comment.
The new data type doesn't support Clear, didn't make much of a difference as you can see from perf report. ArgumentsInstances are the big polluters as they were created for function calls, might not have properties materialized that often.
There was a problem hiding this comment.
You can only say if you run a diff with and without ;)
There was a problem hiding this comment.
Shouldn't be hard to implement, will add.
* HashHelpers to StringDictionarySlim
| @@ -298,14 +301,14 @@ public JsValue Freeze(JsValue thisObject, JsValue[] arguments) | |||
| { | |||
| if (desc.Writable) | |||
| { | |||
| var mutable = desc as PropertyDescriptor ?? new PropertyDescriptor(desc); | |||
There was a problem hiding this comment.
Why aren't we cloning it anymore? Are these immutable?
There was a problem hiding this comment.
R# showed that this will never be evaluated, every property descriptor is a PropertyDescriptor..
* support Clear
I have replaced the StructDictionary with slightly modified DictionarySlim. This version uses string keys directly (hence the name StringDictionarySlim) and doesn't check for collisions as we don't need to detect multi-threaded access.
I also removed separate dictionary _intrinsicProperties as so far I've seen need, we can probably add back later if needed.
Performance results generally seem to be within the waving my laptop does, but the greatest benefit can be seen in UncacheableExpressionsBenchmark where more realistic object mapping happens against the new dictionary type.
Esprima.Benchmark.DromaeoBenchmark
Jint.Benchmark.ArrayBenchmark
Jint.Benchmark.UncacheableExpressionsBenchmark