CODEWITHSUNDEEP
performanceprofiling
Mircea Ispas
Mircea Ispas

Reputation: 20780

Low hardware simulation for performance profiling

I need to optimize the app I'm working on and I can't get reliable profiling data on my development machine. The app should run on low end ARM hardware on QNX, but from logistic reasons I don't have access to the final hardware for profiling.

I've tried to do profiling on my development machine, but as you can imagine everything is so fast that I can't pin point the slow parts. I've created a Linux virtual machine with reduced memory and CPU cores count, but they are still too fast compared to the final hardware.

Is it possible to reduce the CPU clock speed/ram speed/disk speed in a virtual machine to simulate low performance hardware or is there any other way to get relevant profiling data on my development machine?

Considering the app is processing several gigabytes of data I assume disk access is a major bottleneck and limiting disk speed might help

I can use any (as in most open source and commercially available) tool/approach that runs on Windows/Linux/MacOS on real or virtual machine.

Upvotes: 1

Views: 220

Answers (1)

SCCC
SCCC

Reputation: 351

This URL describes how to limit disk bandwidth on VirtualBox images. You could run a Linux VM on Virtualbox and use this method to limit disk access speeds, turn off Disk Caching using suggestions from this answer and profile your application. Alternatively you can download QNX SDP, which comes with the option of a prebuilt x86_64 Virtual Machine image that can be run using VMWare/Virtualbox/qemu

My previous experiences with QNX on armv7 and x86_64 suggest that the devb-sdmmc driver is possibly a bottleneck when working with a lot of big files being read from flash storage. devb-sdmmc and io-blk often require fine tuning of the drivers with proper cache, block, read-ahead size and other parameters helps improve disk access performance.

Upvotes: 1

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