agarny
23rd June 2014, 15:09
Hi,
I am developing an application that can be used to run mathematical simulations. Each simulation is run in its own thread. Every works fine and everything, except that I recently noticed that if I have two simulations S1 and S2, then if I first run S1 then it will run ‘slowly’. From there, if I rerun S1 or run S2, then S1 or S2 will run ‘fast’. In other words, no matter which simulation I run the first time, it will run ‘slowly’ while any subsequent simulation will run fast. Just to give you an idea, the first time I run a particular simulation, it takes ~28.9 s to run while subsequent runs of that same simulation take ~12.7 s (!!).
In an attempt to pinpoint what might be causing this, I tried my application on Windows and Linux, and I didn’t experience that behaviour. From there, I thought I would try my application on older versions of OS X (I tried Mac OS X 10.7 and OS X 10.8), and again I didn’t experience that behaviour. Next, I decided to test previous versions of my application and they all experienced the same behaviour on OS X 10.9, but not on Mac OS X 10.7 or OS X 10.8.
So, there is clearly an issue between my application and OS X 10.9. Now, it may be worth pointing out that the different versions of my application were built using different versions of Qt (as well as of LLVM, of which I use its JIT engine to run my simulations). So, could it be that there is something in Qt that is not working ‘properly’ with OS X 10.9 (e.g. threading)? Alternatively, maybe there is something in LLVM that I don’t do and which is ‘required’ to work ‘properly’ in OS X 10.9?
So, has anyone ever come across something similar and/or would know how to fix this issue?
Cheers, Alan.
I am developing an application that can be used to run mathematical simulations. Each simulation is run in its own thread. Every works fine and everything, except that I recently noticed that if I have two simulations S1 and S2, then if I first run S1 then it will run ‘slowly’. From there, if I rerun S1 or run S2, then S1 or S2 will run ‘fast’. In other words, no matter which simulation I run the first time, it will run ‘slowly’ while any subsequent simulation will run fast. Just to give you an idea, the first time I run a particular simulation, it takes ~28.9 s to run while subsequent runs of that same simulation take ~12.7 s (!!).
In an attempt to pinpoint what might be causing this, I tried my application on Windows and Linux, and I didn’t experience that behaviour. From there, I thought I would try my application on older versions of OS X (I tried Mac OS X 10.7 and OS X 10.8), and again I didn’t experience that behaviour. Next, I decided to test previous versions of my application and they all experienced the same behaviour on OS X 10.9, but not on Mac OS X 10.7 or OS X 10.8.
So, there is clearly an issue between my application and OS X 10.9. Now, it may be worth pointing out that the different versions of my application were built using different versions of Qt (as well as of LLVM, of which I use its JIT engine to run my simulations). So, could it be that there is something in Qt that is not working ‘properly’ with OS X 10.9 (e.g. threading)? Alternatively, maybe there is something in LLVM that I don’t do and which is ‘required’ to work ‘properly’ in OS X 10.9?
So, has anyone ever come across something similar and/or would know how to fix this issue?
Cheers, Alan.