Re: Should an ISA contain

From	Stefan Monnier <monnier@iro.umontreal.ca>
Newsgroups	comp.arch
Subject	Re: Should an ISA contain
Date	2026-05-15 13:11 -0400
Organization	A noiseless patient Spider
Message-ID	<jwvik8ovc4x.fsf-monnier+comp.arch@gnu.org> (permalink)
References	<1778283261-5857@newsgrouper.org> <10tr1qh$nfa1$1@dont-email.me> <2026May11.083942@mips.complang.tuwien.ac.at> <10u2uvb$31od3$1@dont-email.me> <1778722602-5857@newsgrouper.org>

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> Consider a GBOoO machine under sequential consistency, a LD which
> can have its address calculated early cannot leave the CPU area
> until all older stores currently in flight have left the CPU area.
> This would dramatically add to L1 cache miss latency, and would
> add moderately to L1 cache hit latency.

Can't the GBOoO send the LD out early/speculatively, and do a kind of
branch-recovery if that memory location is later modified is a way that
changes what the LD should have received?

Of course, that too comes with a cost (that of keeping track of all
those memory accesses that may have to be re-done), but it's not obvious
to me that it would necessarily be impractical.


=== Stefan

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Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-08 23:34 +0000
  Re: Should an ISA contain EricP <ThatWouldBeTelling@thevillage.com> - 2026-05-08 19:52 -0400
    Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-09 18:44 +0000
  Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-08 21:36 -0500
  Re: Should an ISA contain Stefan Monnier <monnier@iro.umontreal.ca> - 2026-05-09 23:27 -0400
  Re: Should an ISA contain Robert Finch <robfi680@gmail.com> - 2026-05-10 02:04 -0400
    Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-10 17:26 +0000
      Adding to: Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-10 21:03 +0000
        Re: Adding to: Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-13 21:11 -0400
      Re: Should an ISA contain scott@slp53.sl.home (Scott Lurndal) - 2026-05-11 14:27 +0000
        Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-11 18:18 +0000
  Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-10 18:45 -0400
    Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-11 00:33 +0000
      Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-10 21:43 -0400
        Re: Should an ISA contain anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-11 07:29 +0000
          Re: Should an ISA contain scott@slp53.sl.home (Scott Lurndal) - 2026-05-11 14:32 +0000
          Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-11 18:09 +0000
          Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-13 20:18 -0400
            Re: Should an ISA contain scott@slp53.sl.home (Scott Lurndal) - 2026-05-14 14:57 +0000
              Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-20 20:27 -0400
        Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-11 18:00 +0000
    Re: Should an ISA contain anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-11 06:39 +0000
      Re: Should an ISA contain Paul Clayton <paaronclayton@gmail.com> - 2026-05-13 18:46 -0400
        Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-14 01:36 +0000
          Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-15 03:08 -0500
          Re: Should an ISA contain Stefan Monnier <monnier@iro.umontreal.ca> - 2026-05-15 13:11 -0400
            implementing sequential consistency (was: Should an ISA contain) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-16 05:57 +0000
              Re: implementing sequential consistency (was: Should an ISA contain) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-16 18:04 +0000
                Re: implementing sequential consistency Terje Mathisen <terje.mathisen@tmsw.no> - 2026-05-16 20:50 +0200
                Re: implementing sequential consistency MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-16 23:01 +0000
        Re: Should an ISA contain anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-14 14:48 +0000
  Re: Should an ISA contain anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-11 06:07 +0000
    Re: Should an ISA contain Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-05-13 07:02 +0000
      Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-14 12:22 -0500
        Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-14 18:31 +0000
          Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-14 20:07 -0500
        Re: Should an ISA contain "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-05-15 14:13 -0700
          Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-17 12:16 -0500
            Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-17 22:08 +0000
            Re: Should an ISA contain "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-05-18 17:14 -0700
      Re: Should an ISA contain Andy Valencia <vandys@vsta.org> - 2026-05-14 18:53 -0700
        Re: Should an ISA contain BGB <cr88192@gmail.com> - 2026-05-15 00:29 -0500
  Re: Should an ISA contain quadi <quadibloc@ca.invalid> - 2026-05-19 20:20 +0000
    Re: Should an ISA contain MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-05-19 21:04 +0000
  Re: Should an ISA contain kegs@provalid.com (Kent Dickey) - 2026-05-20 18:06 +0000

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