[#106355] [Ruby master Bug#18373] RBS build failure: '/include/x86_64-linux/ruby/config.h', needed by 'constants.o'. — "vo.x (Vit Ondruch)" <noreply@...>
Issue #18373 has been reported by vo.x (Vit Ondruch).
28 messages
2021/12/01
[ruby-core:106659] [Ruby master Feature#18364] Add GC.stat_pool for Variable Width Allocation
From:
"Eregon (Benoit Daloze)" <noreply@...>
Date:
2021-12-14 15:41:06 UTC
List:
ruby-core #106659
Issue #18364 has been updated by Eregon (Benoit Daloze).
I forgot to mention, I think `GC.stat` is expected to be reasonably fast as e.g. it might be done on every request for monitoring.
OTOH capturing per-heap information is typically significantly slower (at least it is on JVM), and so providing that information in a separate method avoids making `GC.stat` slower.
peterzhu2118 (Peter Zhu) wrote in #note-14:
> If callers want to prevent the probe effect from calls to `GC.stat`, they have to not only create a hash beforehand, but also do a call to `GC.stat`.
> Since the first call can trigger GC, I don't think it's unreasonable to also allocate objects.
That's a fair point, and probably somewhat already needed as otherwise the Hash will typically need some extra (internal) allocations to fit enough entries.
I think we should document this better in the `GC.stat` docs.
----------------------------------------
Feature #18364: Add GC.stat_pool for Variable Width Allocation
https://bugs.ruby-lang.org/issues/18364#change-95331
* Author: peterzhu2118 (Peter Zhu)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
# GitHub PR: https://github.com/ruby/ruby/pull/5177
We're proposing an API to get statistics for size pools for Variable Width Allocation similar to `GC.stat`. This will make it easier for us (and other developers) to tune VWA.
Before 3.1 release, we plan to keep this method hidden from the documentation using `:nodoc:` since it is not useful when not using VWA.
For example:
```ruby
# Get stats for size pool 2
puts GC.stat_pool(2)
#=> {:slot_size=>160, :heap_allocatable_pages=>80, :heap_eden_pages=>14, :heap_eden_slots=>1424, :heap_tomb_pages=>0, :heap_tomb_slots=>0}
puts GC.stat_pool(2, :heap_eden_pages)
#=> 14
```
We aim to keep the keys in the outputted hash the same as the keys used in `GC.stat`.
We chose to implement a new method instead of re-using an existing API (`GC.stat`) because the keys returned by `GC.stat_pool` will not be the same as `GC.stat`. We believe that having `GC.stat` return different shapes of hashes based on its arguments is confusing.
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