Messages in this thread | | | Date | Fri, 20 Jan 2023 16:34:37 -0800 | From | "Paul E. McKenney" <> | Subject | Re: Internal vs. external barriers (was: Re: Interesting LKMM litmus test) |
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On Sat, Jan 21, 2023 at 01:03:50AM +0100, Jonas Oberhauser wrote: > > > On 1/21/2023 12:19 AM, Paul E. McKenney wrote: > > On Fri, Jan 20, 2023 at 11:36:15PM +0100, Jonas Oberhauser wrote: > > > > > > On 1/20/2023 10:37 PM, Paul E. McKenney wrote: > > > > Just out of curiosity, are you [set] up to run LKMM locally at your end? > > > I don't know what exactly that means. I generally run it on wetware. > > > But I sometimes ask Hernan to run Dat3M (on his machine) over all the litmus > > > tests in your repo to spot any obvious problems with variations I consider. > > > I don't think Dat3M is feature-complete with herd at the moment, just > > > unbelievably faster. For example I think it ignores all flags in the cat > > > files. > > > Oh, I just remembered that I also installed herd7 recently to make sure that > > > any patches I might send in satisfy herd7 syntax requirements (I think you > > > called this diagnostic driven development?), but I haven't used it to really > > > run anything. > > > > > > Is it too obvious that my words usually aren't backed by cold machine logic? > > Well, there was this in one of your messages from earlier today: "I'm not > > going to get it right today, am I?" And I freely confess that this led > > me to suspect that you might not have been availing yourself of herd7's > > opinion before posting. ;-) > The main reason I might usually not consult herd7's opinion is that it often > takes a while to write a test case in a way herd7 accepts and treats as > intended, but then even so the fact that some tests pass may just give some > false confidence when some tricky case is being missed. > So I find the investment/increased confidence ratio to not yet be at the > right point to do this when communicating somewhat informally on the mailing > list, which is already taking quite a bit of my time (but at least I'm > learning a lot during that time about stuff like RCU/SRCU, history of LKMM, > etc.). > If I need to be more confident I'll use herd7 to make sure the syntax is > correct and as a sanity check, and some paper or Coq proofs to be confident > in the logic. > > If you feel that I'm wasting the lists' time too much by making these kind > of mistakes, let me know and I'll reconsider.
Not a goal of mine, actually.
The only thing that I will add is that I cheat horribly by creating new litmus tests by existing ones. ;-)
Thanx, Paul
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