From: normalperson@...
Date: 2014-12-11T23:08:18+00:00
Subject: [ruby-core:66793] [ruby-trunk - Feature #10585] struct: speedup struct.attr = v for first 10 attributes and struct[:attr] for big structs

Issue #10585 has been updated by Eric Wong.


 benchmark results on r48774 (Xeon E3-v1230 v3):
 
 Speedup ratio: compare with the result of `trunk' (greater is better)
 name	built
 loop_whileloop2	1.001
 vm2_struct_big_aref_hi*	1.006
 vm2_struct_big_aref_lo*	1.000
 vm2_struct_big_aset*	1.005
 vm2_struct_big_href_hi*	1.466
 vm2_struct_big_href_lo*	1.213
 vm2_struct_big_hset*	1.305
 vm2_struct_small_aref*	1.010
 vm2_struct_small_aset*	2.604
 vm2_struct_small_href*	1.215
 vm2_struct_small_hset*	1.215
 
 Comments on patches:
 
 * [1/4] struct.c: speedup struct.name = v for small structs
   I agree this makes a noticeable improvement, but I am also not
   in favor of more specialized C code.  One day, I hope we
   can remove the current optimizations for <10 getters with JIT.
 
 * [2/4] struct.c: cache member definition in a subclass
   I think NIL_P(var) is preferred over "var != Qnil".
   Overall, I think this patch makes sense on its own.
 
 * [3/4] benchmark struct[:name]
   Good :)
 
 * [4/4] struct.c: speedup for big structs
   Oops, I totally missed some of these in [Feature #10575]
   I'm unsure about having a custom hash table in there
   is best, perhaps it can be extracted and reused for
   other things (fstring).

----------------------------------------
Feature #10585: struct: speedup struct.attr = v for first 10 attributes and struct[:attr] for big structs
https://bugs.ruby-lang.org/issues/10585#change-50367

* Author: Yura Sokolov
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
----------------------------------------
0001 - Define optimized setters for first 10 attributes.

0002 - Cache members definition in an subclasses - it is safe cause it could be modified/overloaded.
And use `rb_attr_get` to lookup definition - it is safe cause result is checked later and `Qnil` is treated as error.

0003,0004 - Use custom hash structure (on top of Array) to lookup members index in a big structure.
Well, I doubt that big structures are useful, so I will not grieve if 0004 is not accepted.

---Files--------------------------------
0001-struct.c-speedup-struct.name-v-for-small-structs.patch (2.33 KB)
0002-struct.c-cache-member-definition-in-a-subclass.patch (1.09 KB)
0003-benchmark-struct-name.patch (2.42 KB)
0004-struct.c-speedup-for-big-structs.patch (5.47 KB)


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