[Lldb-commits] [lldb] adds additional information to the ProcessInfo object for elf processes (PR #88995)

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jimingham wrote:


> On Apr 16, 2024, at 5:17 PM, Fred Grim ***@***.***> wrote:
> 
> 
> These seem like fairly POSIX-y bits of data, is there not a Posix way to get these (so other posix systems will also get this info?)
> 
> Not that I know of for arbitrary processes in linux. fwiw the original code without these values got similar bits out of the proc filesystem
> 
That's sad, but not your doing...

> Also, it looks like you added user time and system time information, but you didn't test that those get valid values.
> 
> I did not. My concern here is that this would make for flaky tests. The issue is that these times are going to be very dependent on the cpus they are scheduled to, what else is running on that same machine and so on. I guess we could do a bunch of stuff to pin the unit test process in place and make it more controllable but that tends to imply permissions for the host executing the unit test. Or maybe you were thinking of another way? I am all ears if so.
> 

The user and system times should be monotonically increasing.  So you could stop at a breakpoint, fetch the times, then run your program through a little spin loop to burn some CPU before hitting a second breakpoint.   Then get the times again and assert that they are > the first set. You could also set a timer in the test between the first and second stop and assert that the difference in system and user time is less than or equal to the timer difference.  A single threaded program can only run on one core at a time, so that should always be true.

Jim


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https://github.com/llvm/llvm-project/pull/88995