• State Not Answered
  • Locked Locked
  • Replies 8 replies
  • Subscribers 27 subscribers
  • Views 16298 views
  • Users 0 members are here
Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

performance: single thread looks OK while multi-thread poor .

DaBang

performance: single thread  looks OK while multi-thread ( 8 threads)  poor .as compared to linux64.

arm machine is with 64-core.  it's verified that 8 threads are started. but why is performance much slow？

Thanks

Parents
  • 0

    Dear DaBang,

    It depends on a lot of things, and there is not enough context that we could work on.

    Two possibilities, though:
    1) with more threads and more core in use, temperature could increase drastically, then thermal management driver could play and throttle CPUs.

    2) the workload is implemented using shared memory space with global variables and you suffer from false sharing. When you run a single threaded version, there is no memory thrashing, while a multithreaded version may thrash memory at each access (cache invalidation, cleaning and fetch back and forth between cores).

    Best Regards,
    Willy

Reply
  • 0

    Dear DaBang,

    It depends on a lot of things, and there is not enough context that we could work on.

    Two possibilities, though:
    1) with more threads and more core in use, temperature could increase drastically, then thermal management driver could play and throttle CPUs.

    2) the workload is implemented using shared memory space with global variables and you suffer from false sharing. When you run a single threaded version, there is no memory thrashing, while a multithreaded version may thrash memory at each access (cache invalidation, cleaning and fetch back and forth between cores).

    Best Regards,
    Willy

Children
No data