Feature #10274: [PATCH 0/2] more rb_iseq_t reductions (and more planned)

• Status: Closed
• Assignee: normalperson (Eric Wong)
• Target version: -

[normalperson (Eric Wong)]

Both of these are pretty simple, low impact patches:

We are close to being able to fit rb_iseq_t in four 64 byte
cache line (we are 262 bytes after these patches,
a milestone is <= 256 bytes).

• [PATCH 1/2] iseq: reduce from 280 to 272 bytes

  • arg_simple is limited to 3 possible values: 0, 1, and 2
  • arg_keyword_check is a boolean
  • flip_cnt should be int to enforce portable code between 64-bit and
    32-bit systems and must fit in FIXNUM space.
    I doubt anybody would notice if flip_cnt (or any arg counters)
    were 8 bits, even.

• [PATCH 2/2] iseq: remove iseq->iseq field (270 => 262 bytes on 64-bit)

  We may store the original iseq after the encoded iseq to reduce
  allocation overhead and use a boolean to denote whether or not
  the iseq_encoded field contains data at the end.

  This simplifies iseq_free and iseq_memsize a little, too.

I will commit in a week or so unless there are objections.

Future:

Move some keyword-related fields into its own struct (similar to
catch table). Maybe compile_data can be split off.

[normalperson (Eric Wong)]

• File 0002-iseq-remove-iseq-iseq-field-270-262-bytes-on-64-bit.patch 0002-iseq-remove-iseq-iseq-field-270-262-bytes-on-64-bit.patch added

[normalperson (Eric Wong)]

[e-mail] wrote:

File 0002-iseq-remove-iseq-iseq-field-270-262-bytes-on-64-bit.patch added

Ugh, forget 2/2. I forgot your comment in [ruby-core:64883] already
on out-of-tree compilers. But I may still overload this field
for compile_data in the future (but I guess I can't use anonymous union
feature of GNU C :x)

[nobu (Nobuyoshi Nakada)]

arg_simple is 0..3, not 0..2.

[ko1 (Koichi Sasada)]

-1 because of readability.
But it is possible that nobody reads it.

I don't against it but I may fix it later.

[normalperson (Eric Wong)]

I reject 0002, but I don't think 0001 hurts readability.
I will update arg_simple to 0..3 from nobu's comment.

[naruse (Yui NARUSE)]

• Target version deleted (2.2.0)

[normalperson (Eric Wong)]

• Status changed from Open to Closed
• Assignee changed from ko1 (Koichi Sasada) to normalperson (Eric Wong)