Re: [PATCH] NUMA spinlock [BZ #23962]

["马凌(彦军)" <ling dot ml at antfin dot com>]

在 2019/1/15 上午7:26，“Torvald Riegel”<triegel@redhat.com> 写入:

    On Wed, 2018-12-26 at 10:50 +0800, Ma Ling wrote:
    > 2. Critical Section Integration (CSI)
    > Essentially spinlock is similar to that one core complete critical
    > sections one by one. So when contention happen, the serialized works
    > are sent to the core who is the lock owner and responsible to execute
    > them, that can save much time and power, because all shared data are
    > located in private cache of the lock owner.
    
    I agree that this can improve performance because of potentially both
    increasing data locality for the critical sections themselves and
    decreasing contention in the lock.  However, this will mess with thread-
    local storage and assumptions about what OS thread a critical section runs
    on.
  Ling: yes, we have to consider it when applying numa spinlock.  
    Maybe it's better to first experiment with this change in semantics in C++;
    ISO C++ Study Group 1 on parallelism and concurrency is much deeper into
    this topic than the glibc community is.  This isn't really a typical lock
    anymore when you do that, but rather a special kind of execution service
    for small functions; the study group has talked about executors that
    execute in guaranteed sequential fashion.
 Ling: thanks for your suggestion, we would like to think about it seriously.