[ruby-core:99572] [Ruby master Bug#17031] `Kernel#caller_locations(m, n)` should be optimized
From:
merch-redmine@...
Date:
2020-08-12 18:50:38 UTC
List:
ruby-core #99572
Issue #17031 has been updated by jeremyevans0 (Jeremy Evans).
Status changed from Closed to Open
Reopening this as the commit had to be reverted as CI showed issues in `backtrace_mark`. I can't work on debugging this right away, so someone is welcome to look into fixing this in the meantime.
----------------------------------------
Bug #17031: `Kernel#caller_locations(m, n)` should be optimized
https://bugs.ruby-lang.org/issues/17031#change-87040
* Author: marcandre (Marc-Andre Lafortune)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
`Kernel#caller_locations(1, 1)` currently appears to needlessly allocate memory for the whole backtrace.
It allocates ~20kB for a 800-deep stacktrace, vs 1.6 kB for a shallow backtrace.
It is also much slower for long stacktraces: about 7x slower for a 800-deep backtrace than for a shallow one.
Test used:
```ruby
def do_something
location = caller_locations(1, 1).first
end
def test(depth, trigger)
do_something if depth == trigger
test(depth - 1, trigger) unless depth == 0
end
require 'benchmark/ips'
Benchmark.ips do |x|
x.report (:short_backtrace ) {test(800,800)}
x.report (:long_backtrace ) {test(800, 0)}
x.report (:no_caller_locations) {test(800, -1)}
end
require 'memory_profiler'
MemoryProfiler.report { test(800,800) }.pretty_print(scale_bytes: true, detailed_report: false)
MemoryProfiler.report { test(800, 0) }.pretty_print(scale_bytes: true, detailed_report: false)
```
Found when checking memory usage on RuboCop.
--
https://bugs.ruby-lang.org/
Unsubscribe: <mailto:[email protected]?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>