MATLAB 2017a was running properly, but suddenly became very slow

Hello,

I am running a big code in MATLAB 2017a in windows 10 to perform some data assimilation. The code calls cygwin to run a software written in C, the result of this software is analyzed and processed. My code was running as expected but it suddenly became very slow for some reason. I uninstalled and reinstalled MATLAB which was of no use. Even the boot speed is slow. I ran the 'bench' code and got:

bench
      0.1788    0.1172    0.2570    0.0989    2.2075    1.9787

System specs are i7 quad core, 16gb RAM, 2.60GHz. If anyone has an idea that could help solve the problem, please let me know. Thanks!

[Abhishek Subramanian]

I uninstalled MATLAB 2017a and installed 2016b. Now my code runs as fast as it used to. I do not know why the code suddenly started running slow in 2017a.

[Star Strider]

Contact Support (link).

It would be interesting to know what the problem is, and the correct solution. MathWorks may have ideas that elude us here.

[Darío Pérez]

Similar problem here still unresolved. Please refer to my comment in: Why my Matlab 2017a is so slow for even simple commands?

[Jan]

"Even the boot speed is slow" - this means, that it is not a Matlab problem and the question is off-topic in this forum. Maybe a problem with overheating of the CPU or a trojan which let the CPU search for bitcoins?

Answer 1

[Philip Borghesani]

Completely outlandish idea. You could check if Windows enabled the fault tolerant heap for MATLAB. You can check by looking for this registry entry: Go to the HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER versions of Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\matlab.exe and delete the Fault­Tolerant­Heap entry. Information came from this stack overflow question.

[Abhishek Subramanian]

I went to

Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers

there I saw 'C:\Program Files\MATLAB\R2017a\bin\matlab.exe' with value data '~ WIN8RTM'. Is this the FaultTolerantHeap that I have to delete?

Also, I uninstalled MATLAB2017a from my system and deleted related files.

[Philip Borghesani]

That may be something else but it could still have caused the problem, no recent MATLAB should need any AppCompatFlags to work properly on Windows 10. I would go ahead and delete any keys with matlab.exe in them.

[Abhishek Subramanian]

Thank you for your answer. I am unable to download 2017a at the moment to try it out. Hopefully this suggestion will be helpful for others who might face a similar issue in the future.

Answer 2

[Don Zheng]

The bench outputs look normal. You might want to profile your code and first identify which section of the code is running slow.

[Abhishek Subramanian]

Bench test in MATLAB 2016b gave:

0.1895    0.1146    0.0582    0.0968    0.5144    0.5662

indicating that the performance is much better than what was seen in MATLAB 2017a

[Jan]

You cannot compare the benchmark output between different Matlab versions, because the code of bench.m might have changed. Care for using the same function to be sure: Create a copy of bench.m and call it bench2016b.m and run it in both versions.