[ruby-core:113265] [Ruby master Bug#4040] SystemStackError with Hash[*a] for Large _a_
From:
"k0kubun (Takashi Kokubun) via ruby-core" <ruby-core@...>
Date:
2023-04-16 04:51:44 UTC
List:
ruby-core #113265
Issue #4040 has been updated by k0kubun (Takashi Kokubun).
> It would be good to get benchmark results from Linux, so if someone could contribute that, I would appreciate it.
I have a linux-x86_64 environment with CPU frequency scaling disabled, so I benchmarked [your PR](https://github.com/ruby/ruby/pull/7522) with yjit-bench. I used `--category headline` because other benchmarks are less important in practice.
```
before: ruby 3.3.0dev (2023-04-14T03:43:46Z master 3733ee835b) [x86_64-linux]
after: ruby 3.3.0dev (2023-04-15T06:35:36Z large-array-splat-.. a0eb73211c) [x86_64-linux]
-------------- ----------- ---------- ---------- ---------- ------------ -------------
bench before (ms) stddev (%) after (ms) stddev (%) before/after after 1st itr
activerecord 65.6 0.4 65.8 0.3 1.00 0.99
erubi_rails 18.7 1.3 18.7 12.4 1.00 1.02
hexapdf 2164.2 0.4 2181.5 0.8 0.99 0.98
liquid-c 57.0 1.6 57.0 1.9 1.00 0.99
liquid-compile 52.6 0.6 52.4 0.6 1.00 1.00
liquid-render 139.8 1.3 140.2 1.1 1.00 1.00
mail 118.1 0.1 118.7 0.2 1.00 1.00
psych-load 1707.5 0.2 1750.9 0.1 0.98 0.97
railsbench 1907.4 0.8 1929.4 0.8 0.99 0.99
ruby-lsp 59.5 10.3 59.4 11.9 1.00 0.98
sequel 65.6 0.2 65.6 0.2 1.00 1.00
-------------- ----------- ---------- ---------- ---------- ------------ -------------
```
I tried running them a few times. In `before/after`, psych-load is stably 2% slower. hexapdf and railsbench show a 1% slowdown, which may be insignificant. Other benchmarks seem to have no difference.
----------------------------------------
Bug #4040: SystemStackError with Hash[*a] for Large _a_
https://bugs.ruby-lang.org/issues/4040#change-102826
* Author: runpaint (Run Paint Run Run)
* Status: Open
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
* ruby -v: ruby 1.9.3dev (2010-11-09 trunk 29737) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
=begin
I've been hesitating over whether to file a ticket about this, so please feel free to close if I've made the wrong choice.
I often use Hash[*array.flatten] in IRB to convert arrays of arrays into hashes. Today I noticed that if the array is big enough, this would raise a SystemStackError. Puzzled, I looked deeper. I assumed I was hitting the maximum number of arguments a method's argc can hold, but realised that the minimum size of the array needed to trigger this exception differed depending on whether I used IRB or not. So, presumably this is indeed exhausting the stack...
In IRB, the following is the minimal reproduction of this problem:
Hash[*130648.times.map{ 1 }]; true
I haven't looked for the minimum value needed with `ruby -e`, but the following reproduces:
ruby -e 'Hash[*1380888.times.map{ 1 }]'
I suppose this isn't technically a bug, but maybe it offers another argument for either #666 or an extension of #3131.
=end
--
https://bugs.ruby-lang.org/
______________________________________________
ruby-core mailing list -- ruby-core@ml.ruby-lang.org
To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org
ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/