| IDL performance, IDL_IDLBridge and multiple instances [message #93895] |
Fri, 18 November 2016 04:13  |
Laurent G.
Messages: 4
Registered: August 2016
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Junior Member |
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Hi,
i'm doing number crunching in IDL 8.4 / Win7 / 64Bit and developed a simple IDL_IDLBridge construct to speed up a process. The process loads a single file, runs for about one hour while outputting log information, saves a new file and stops. I use 8 IDL_IDLBridge slaves to start 8 of these processes at the same time (8 core system). I poll every 10s with bridge->status() to check if a process is done. RAM is not a problem (10GB of 16GB available with all processes running). I used this technique before and got quasi linear speedups.
But this time the CPU load stays at 18%. Logging information tells me all 8 slave processes are running, but progressing very slowly. They seem to share a single core. Disc activity is very low and roughly corresponds to the 10KB logfile per hour and process.
All slaves run the same code, but with different parameters for input/output files. One of the main subroutines called contains a "common" block. It is first time i used that concept together with IDL_IDLBridge. The results look correct, so i guess this block is not cross-synchronized between slaves?
Is calling a subroutine limited to a single process/core?
Starting 3 instances of the IDL, each running 8 IDL_IDLBridge slaves also leads to ~18% CPU load. Again all 3x8 slaves are making progress, but very, very slowly, corresponding roughly to a single core shared by all 3x8 processes !?
Do those 3 IDL instances intercommunicate?
The problem happens on 2 windows 7 machines. Both machines run other IDL code just fine with all 8 cores loaded.
Thanks,
Laurent Gilson
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