Re: [seL4] seL4 System Utilization / Benchmark

You should be able to call seL4 syscalls from a CAmkES component. Just include the right headers (and link the library if necesary). Note that if the syscalls require caps, then you are on your own wrt how to get the caps. Ihor

On 18 Jan 2017, at 12:29 pm, Andrew Gacek wrote:

Thanks Adrian. This is a useful start. It sounds like the easiest thing may be to overwrite some syscall that I don't use to loop over all the threads in the kernel and print out their debugging info.

Also, I've never called raw seL4 system calls from a camkes component before. Is it just a matter of calling seL4_BenchmarkResetLog() or seL4_BenchmarkFinalizeLog() directly in the control code for one of my components?

-Andrew

On Tue, Jan 17, 2017 at 7:23 PM, wrote:

...

Hi Andrew,

There is some code already in the kernel to help you do this, although it is tested and fixed on an as used basis so may or may not work as I describe. You can enable the the thread utilization tracking with make menuconfig -> seL4 Kernel -> Build Options -> Enable benchmarks -> Track threads and kernel utilisation time Once enabled you gain the following relevant functions

seL4_BenchmarkResetLog() Reset idle time and total run time and start capturing utilization information

seL4_BenchmarkFinalizeLog() Calculate idle time, total run time and stop capturing utilization information

seL4_BenchmarkGetThreadUtilisation(seL4_Word tcb_cptr) Retrieve the utilization for a particular thread where seL4_GetMR(0) == Thread utilization (in cycles) of this (tcb_cptr) thread seL4_GetMR(1) == Idle thread utilization (in cycles) between the last call to Reset and Finalize log seL4_GetMR(2) == Totall execution time (in cycles) between the last call to Reset and Finalize log

seL4_BenchmarkResetThreadUtilisation(seL4_Word tcb_cptr) Reset the utilization of this thread.

The main problem with this API is that it requires you to have caps to all the threads you wish to get the information of, which in CAmkES is generally only the capdl-loader application. It is also designed with the idea that you want to reset the utilization counts at the point you're querying them, i.e. you're doing some kind of benchmark and you just want utilization over that benchmark.

Hope this provides some use to you.

Adrian

On Wed 18-Jan-2017 9:59 AM, Andrew Gacek wrote:

Hi,

I'm interested in seeing how much of the CPU is being used by the various threads in my (camkes) application. I'd like a simple "Task Manager" style report of the form:

70% idle 25% can_obj_7_0_control_9_tcb 5% can_obj_7_Int_3_0000_tcb 0% can_obj_7_0_fault_handler_15_ 0000_tcb etc

I've tried poking around libsel4bench, but I don't see any obvious way of benchmarking the whole system. From what I can tell, it's mostly designed to get cycle counts from specific code segments. Is that right? What's the best way to go about benchmarking the whole system? It's only for debugging, so I'm willing to make some quick-and-dirty changes to the kernel just to see the results.

Thanks, Andrew

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