Messages in this thread | | | Subject | Re: [PATCH 1/1] Fix: trace sched switch start/stop racy updates | From | Valentin Schneider <> | Date | Mon, 19 Aug 2019 11:34:47 +0100 |
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On 18/08/2019 00:00, Paul E. McKenney wrote: [...] > Linus noted that he believes that compilers for architectures supporting > Linux can be trusted to avoid store-to-load transformations, invented > stores, and unnecessary store tearing. Should these appear, Linus would > report a bug against the compiler and expect it to be fixed. > >> I'll be honest, it's not 100% clear to me when those optimizations can >> actually be done (maybe the branch thingy but the others are dubious), and >> it's even less clear when compilers *actually* do it - only that they have >> been reported to do it (so it's not made up). > > There is significant unclarity inherent in the situation. The standard > says one thing, different compilers do other things, and developers > often expect yet a third thing. And sometimes things change over time, > for example, the ca. 2011 dictim against compilers inventing data races. > > Hey, they didn't teach me this aspect of software development in school, > either. ;-) >
Gotta keeps things "interesting" somehow, eh...
Thanks for the clarifications.
> Thanx, Paul >
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