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Feature #10050
closed[PATCH 0/2] reduce rb_io_t to 192 bytes (from 216) on 64-bit
Description
This will allow x86-64 machines to only use 3 cache lines instead of 4
(where cache size == 64).
Hopefully there are other 64-bit architectures which benefit, too.
This is also public ABI breakage, so I hope to commit it around when a patch for
Feature #10034 (re_pattern_buffer reduction) gets committed to reduce testers'
need to rebuild C exts.
Files
Updated by normalperson (Eric Wong) about 10 years ago
- File 0001-rb_io_t.patch 0001-rb_io_t.patch added
Updated by normalperson (Eric Wong) about 10 years ago
Updated by normalperson (Eric Wong) about 10 years ago
I forgot to note this the last publically-visible struct which may be
packed. Internals for the others are defined privately:
$ pahole -P ruby
rb_thread_struct 1016 1000 16
rb_execarg 160 152 8
io_internal_writev_struct 24 16 8
io_advise_struct 32 24 8
waitpid_arg 24 16 8
load_file_arg 48 40 8
rb_econv_t 200 184 16
rb_transcoder 160 152 8
rb_context_struct 1312 1304 8
rb_fiber_struct 2304 2296 8
parser_params 320 304 16
Updated by Anonymous about 10 years ago
- Status changed from Open to Closed
- % Done changed from 0 to 100
Applied in changeset r46883.
rb_io_t: shrink from 216 to 200 bytes on 64-bit
- include/ruby/io.h (rb_io_t): shrink to 200 bytes from 216 on 64-bit
This puts us within 8 bytes of being three cache lines instead of
four lines on x86-64. This breaks the ABI.
[Feature #10050]
Updated by ngoto (Naohisa Goto) about 10 years ago
- Related to Bug #10088: Bus Error on Sparc Solaris since r46884 added
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