Article View: comp.arch
Article #10593Re: Atomic operations (Was Re: Living With Old Baggage)
From: John R. Levine
Date: Sat, 04 May 1991 04:34
Date: Sat, 04 May 1991 04:34
13 lines
1186 bytes
1186 bytes
In article <1991May2.201917.15062@dg-rtp.dg.com> hamilton@siberia.rtp.dg.com (Eric Hamilton) writes:
>Now I'm curious. How does one fabricate compare-and-swap out of xmem
>without disabling interrupts?
You can't, at least not without a scheme that uses spin locks which are at
least as bad as disabling interrupts. See Herlihy's article on "Wait-free
Synchronization" in the January TOPLAS. It turns out that CAS is
fundamentally more powerful than most other synchronization primitives.
--
John R. Levine, IECC, POB 349, Cambridge MA 02238, +1 617 492 3869
johnl@iecc.cambridge.ma.us, {ima|spdcc|world}!iecc!johnl
Cheap oil is an oxymoron.
Technical Details
Message-ID:
<1991May04.043452.19482@iecc.cambridge.ma.us>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!world!iecc!johnlReferences:
<14628@encore.Encore.COM> <1991Apr22.175410.9840@decvax.dec.com> <1991May2.201917.15062@dg-rtp.dg.com>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!world!iecc!johnl From: johnl@iecc.cambridge.ma.us (John R. Levine) Newsgroups: comp.arch Subject: Re: Atomic operations (Was Re: Living With Old Baggage) Keywords: 68040 CAS2 Message-ID: <1991May04.043452.19482@iecc.cambridge.ma.us> Date: 4 May 91 04:34:52 GMT References: <14628@encore.Encore.COM> <1991Apr22.175410.9840@decvax.dec.com> <1991May2.201917.15062@dg-rtp.dg.com> Organization: I.E.C.C. Lines: 13