[argobots-discuss] dumping stack information for running ULTs

[Phil Carns]

Hi all,

I followed Shintaro's suggestions from the previous list email thread 
and was able to get a stack dump routine that works as expected.  For 
all pools under my control I can see stack information like this for 
each ULT, with stack unwinding:

    == pool (0x557d5b8c4580) ==
    === ULT (0x7f47429590c1) ===
    id        : 0
    ctx       : 0x7f4742959120
    p_ctx    : 0x7f4742958fe0
    p_link   : (nil)
    stack     : 0x7f47427590c0
    stacksize : 2097152
    #0 0x7f4744461760 in ythread_unwind_stack () <+16> (RSP =
    0x7f4742959010)
    #1 0x7f474445e3dd in ABT_thread_yield () <+157> (RSP = 0x7f4742959020)
    #2 0x7f474447e255 in __margo_hg_progress_fn () <+645> (RSP =
    0x7f4742959040)
    #3 0x7f474446381e in ABTD_ythread_func_wrapper () <+30> (RSP =
    0x7f47429590b0)
    #4 0x7f47444639c1 in make_fcontext () <+33> (RSP = 0x7f47429590c0)
    00007f47427590c0: 0000000000000000 0000000000000000 0000000000000000
    0000000000000000
    00007f47427590e0: 0000000000000000 0000000000000000 0000000000000000
    0000000000000000
    ...

That only works for ULTs that are literally in the pool, though, I 
think.  I don't believe that I am getting information for ULTs that are 
executing (and thus are not presently in a pool data structure).

Is there any way to accomplish that?

I tried to at least get the caller's own stack at least by doing 
something like this:

     ABT_thread_self(&self);
     ABT_info_print_thread_stack(outfile, self);

That almost works, but I'm just getting the raw address information and 
not the translated stack unwinding:

    p_ctx    : 0x7f4742758fb8
    p_link   : (nil)
    stack     : 0x7f4742559000
    stacksize : 2097152
    00007f4742559000: 0000000000000000 0000000000000000 0000000000000000
    0000000000000000
    00007f4742559020: 0000000000000000 0000000000000000 0000000000000000
    0000000000000000
    ...

For completeness it would be nice if the caller's stack were also human 
readable, and even better if I could somehow find stack information for 
ULTs executing on other ESs as well.

For our use case we typically spawn many detached threads into a service 
pool, so we aren't tracking thread references.

thanks,

-Phil


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