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| From | Lawrence D’Oliveiro <ldo@nz.invalid> |
|---|---|
| Newsgroups | comp.arch |
| Subject | Re: Performance of xchg reg,reg |
| Date | 2026-10-14 00:23 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <11ami2v$11dqu$3@dont-email.me> (permalink) |
| References | <2026Oct13.104347@mips.complang.tuwien.ac.at> |
On Tue, 13 Oct 2026 08:43:47 GMT, Anton Ertl wrote: > On Zen5, even a 5-register cycle can be profitably implemented with > xchg when you have no spare register, a 4-register cycle even when > you have a spare register. For Zen4 and Zen3 cyc4 (for mem) and cyc3 > (for reg) are borderline cases, and for shorter cycles xchg is > better. > > On Intel processors, xchg is so slow that it never is profitable to > use it. The slowness takes on extreme values in the E-cores, with > slowdowns by a factor >10 for cyc4 and cyc5. You’d think both companies would be running similar kinds of instruction workloads to find the things worth optimizing in their CPU architectures. But perhaps not ...
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Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-13 08:43 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-14 00:23 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-14 07:00 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-14 22:35 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-14 23:07 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-15 06:05 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-15 07:06 +0000
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-16 09:47 -0400
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-16 16:04 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-17 05:46 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-14 22:29 +0300
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-15 14:21 -0700
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-15 21:42 +0000
Re: Performance of xchg reg,reg Terje Mathisen <terje.mathisen@tmsw.no> - 2026-10-16 14:45 +0200
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-16 05:50 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-16 11:34 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-16 18:23 +0000
Re: Performance of xchg reg,reg scott@slp53.sl.home (Scott Lurndal) - 2026-10-16 20:48 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-16 14:28 -0700
Re: Performance of xchg reg,reg Thomas Koenig <tkoenig@netcologne.de> - 2026-10-17 09:48 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-17 02:50 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-17 17:11 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-17 17:31 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-17 19:39 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-17 23:20 +0300
Re: Documentation (was Re: Performance of xchg reg,reg) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-17 20:54 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) George Neuner <gneuner2@comcast.net> - 2026-10-18 09:45 -0400
Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 14:08 +0000
Re: Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) quadibloc@invalid.com (John Savard) - 2026-10-19 00:09 +0000
Re: Algol 68 (was Re: Documentation) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 01:46 +0000
Re: Algol 68 (was Re: Documentation) quadibloc@invalid.com (John Savard) - 2026-10-21 14:15 +0000
Re: Algol 68 (was Re: Documentation) Niklas Holsti <niklas.holsti@tidorum.invalid> - 2026-10-21 18:34 +0300
Re: Algol 68 (was Re: Documentation) quadibloc@invalid.com (John Savard) - 2026-10-21 19:38 +0000
Re: Algol 68 (was Re: Documentation) aph@littlepinkcloud.invalid - 2026-10-22 09:51 +0000
Re: Algol 68 (was Re: Documentation) Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-10-22 14:15 -0700
Re: Algol 68 (was Re: Documentation) scott@slp53.sl.home (Scott Lurndal) - 2026-10-23 14:08 +0000
Re: PL/I, was Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) John Levine <johnl@taugh.com> - 2026-10-19 03:24 +0000
Re: PL/I, was Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-19 05:34 +0000
Re: Algol 68 Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-18 23:34 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) quadibloc@invalid.com (John Savard) - 2026-10-19 00:18 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-19 01:52 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) George Neuner <gneuner2@comcast.net> - 2026-10-19 14:50 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 02:05 +0000
Re: Algol 68 (was Re: Documentation) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 01:54 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) Thomas Koenig <tkoenig@netcologne.de> - 2026-10-19 07:44 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-19 12:24 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-18 17:48 +0000
Re: Performance of xchg reg,reg George Neuner <gneuner2@comcast.net> - 2026-10-18 08:59 -0400
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 15:08 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 18:43 +0300
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 16:57 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 20:47 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 18:07 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 21:04 +0000
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-18 23:43 -0400
Re: Performance of xchg reg,reg Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-10-19 06:57 -0700
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:27 -0700
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-20 10:00 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 02:00 +0000
Re: Performance of xchg reg,reg scott@slp53.sl.home (Scott Lurndal) - 2026-10-20 14:09 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-20 16:44 -0700
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-20 10:05 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 19:56 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-22 10:54 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-22 22:11 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:40 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 20:54 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 18:25 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-18 18:01 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:59 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:09 +0000
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-18 12:31 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:47 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-18 12:27 -0700
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-19 09:38 -0400
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:08 -0700
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 21:21 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:26 -0700
Re: Performance of xchg reg,reg Joseph Seigh <jseigh_es00@xemaps.com> - 2026-10-19 19:17 -0400
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 22:41 -0700
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-20 16:45 +0000
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