What is ASM.JS?
Many people are using OProfile for system measurements on Linux. This is a very handy profiling tool (supports hardware performance counters and has a very low runtime overhead) although it is in alpha phase. Using OProfile to measure any application performance is a straightforward task on Linux: you should get the latest OProfile for your machine or device, build, configure and run the daemon, and start measuring an application or your whole system. Finally, you can execute several scripts which report the performance numbers to you (according to your reporting requests). It sounds easy, doesn't it?