On 06/09/17 15:26, el es wrote: > On 06/09/17 10:31, Andrea Mauri via Lazarus wrote: >> Il 05/09/2017 22:51, Sven Barth via Lazarus ha scritto: >>> >>> It is however solved if you add a "Yield;" after the Synchronize >>> call. So my suspicion is that the scheduling of Mac OS X is somehow >>> messing things up. Either the scheduling is favoring the one thread >>> while it shouldn't (though even reducing the priority doesn't help) >>> or the UI framework of Mac OS X (and whatever else is involved in >>> the main thread) is so heavy weight that the timeslice of the >>> mainthread is used up more often than not thus leading to the read >>> thread being scheduled much more often. By using Yield (or also >>> Sleep(), but Yield is without any pause) the thread is explicitly >>> giving up its timeslice and that seems to be enough here... >>> >> >> I changed the code following your hints and I added Yield. This is >> not enough, it seems that the application is a little bit more >> responding (I can click on Tedit and after seconds the text is >> highlighted) but not enough to be usable. Actually for me it works >> only if I add at least Sleep(1). It is a pity that there is not a >> unique solution. > > Can you try ThreadSwitch after Sleep ? > > while (not Terminated) do > begin > if eof(f) then > reset(f); > ReadLn(f, newStatus); > if NewStatus <> fStatusText then > begin > fStatusText := newStatus; > //Queue(@ShowStatus); > Synchronize(@Showstatus); > Sleep(5); > ThreadSwitch; /// <<<< > end > else // also you need to cover what happens in ANY OTHER outcome of > any test, e.g. > ThreadSwitch; > // because if NewStatus = fStatusText, you will IMMEDIATELY jump to the > first instruction of the thread > // so adding the ThreadSwitch at the very end of the loop, you give the > rest of the application (the main thread) a chance to > // actually do anything > end; > > Thread.Execute will execute ALL THE TIME if you don't yield/threadswitch in > some code path, and WILL saturate your CPU. > > -l, >
In addition to why this isn't a problem on Windows or Linux: they have supposedly better schedulers... but if not all codepaths on a thread are covered to give some time to main thread, try to imagine what happens: - could the un-yielded code path lead to over-zealous enqueuing of the ShowStatus routine? - if yes, what would happen in such case? -- _______________________________________________ Lazarus mailing list Lazarus@lists.lazarus-ide.org https://lists.lazarus-ide.org/listinfo/lazarus
