RFR: CODETOOLS-7902909: jcstress: Sysfs topology parser should accept duplicate core IDs in different packages

[Aleksey Shipilev]

There is an example on one of the hosts, where jcstress detects the topology as:


Detecting CPU topology and computing scheduling classes:
   Linux, using /sys/devices/system/cpu
   2 packages, 1 core per package, 2 threads per core

   CPU lists:
     Package #0, Core #0, Threads: 0, 1
     Package #1, Core #0, Threads: 0, 1


...whereas the real topology is:


# lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 2
On-line CPU(s) list: 0,1
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 2
NUMA node(s): 1


This is because core #0 is recorded for both packages #0 and #1. This deadlocks the scheduler.

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Commit messages:
 - Fix the parsing properly
 - Handle duplicate core ID example

Changes: https://git.openjdk.java.net/jcstress/pull/40/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jcstress&pr=40&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7902909
  Stats: 151 lines in 6 files changed: 143 ins; 3 del; 5 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/40.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/40/head:pull/40

PR: https://git.openjdk.java.net/jcstress/pull/40