magic-trace seems to find recursion in stack traces not present in application

[rohany]

Thanks for developing magic trace! I've been looking into it recently to investigate some bottlenecks in the Legion runtime system. I'm seeing somewhat corrupted stack traces like this:

When there's no recursion present in the corresponding piece of code: https://gitlab.com/StanfordLegion/legion/-/blob/master/runtime/realm/tasks.cc?ref_type=heads#L1050

I suspect that this is also leading to some amount of dropped data (there are fewer invocations of the function execute_point than I would expect). The attached trace file itself (below) reports several errors when loaded into the magic-trace viewer.

My invocation of the program was:

/scratch/rohany/magic-trace/magic-trace run -multi-thread -- ./task_bench ...

Resulting trace file is attached.

Perf infomation:

rohany@redwood:/scratch/rohany/task-bench/realm_subgraph$ perf --version
perf version 5.15.163

CPU info:

rohany@redwood:/scratch/rohany/task-bench/realm_subgraph$ lscpu
Architecture:             x86_64
  CPU op-mode(s):         32-bit, 64-bit
  Address sizes:          46 bits physical, 48 bits virtual
  Byte Order:             Little Endian
CPU(s):                   32
  On-line CPU(s) list:    0-31
Vendor ID:                GenuineIntel
  Model name:             Intel(R) Core(TM) i9-14900K
    CPU family:           6
    Model:                183
    Thread(s) per core:   2
    Core(s) per socket:   24
    Socket(s):            1
    Stepping:             1
    CPU max MHz:          6000.0000
    CPU min MHz:          800.0000
    BogoMIPS:             6374.40
    Flags:                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni
                           pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single ssbd ibrs ibpb stibp ibrs_enhanced tpr_
                          shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rdseed adx smap clflushopt clwb intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves split_lock_detect avx_vnni dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_e
                          pp hwp_pkg_req umip pku ospke waitpkg gfni vaes vpclmulqdq tme rdpid movdiri movdir64b fsrm md_clear serialize pconfig arch_lbr flush_l1d arch_capabilities
Virtualization features:
  Virtualization:         VT-x
Caches (sum of all):
  L1d:                    896 KiB (24 instances)
  L1i:                    1.3 MiB (24 instances)
  L2:                     32 MiB (12 instances)
  L3:                     36 MiB (1 instance)
NUMA:
  NUMA node(s):           1
  NUMA node0 CPU(s):      0-31
Vulnerabilities:
  Gather data sampling:   Not affected
  Itlb multihit:          Not affected
  L1tf:                   Not affected
  Mds:                    Not affected
  Meltdown:               Not affected
  Mmio stale data:        Not affected
  Reg file data sampling: Mitigation; Clear Register File
  Retbleed:               Not affected
  Spec rstack overflow:   Not affected
  Spec store bypass:      Mitigation; Speculative Store Bypass disabled via prctl and seccomp
  Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitization
  Spectre v2:             Mitigation; Enhanced / Automatic IBRS; IBPB conditional; RSB filling; PBRSB-eIBRS SW sequence; BHI BHI_DIS_S
  Srbds:                  Not affected
  Tsx async abort:        Not affected

This file is a .fxt, renamed to .txt.
trace8.txt