cvs commit: src/sys/amd64/amd64 cpu_switch.S genassym.c machdep.c src/sys/i386/i386 genassym.c machdep.c swtch.s src/sys/ia64/ia64 machdep.c src/sys/kern kern_umtx.c src/sys/sys pcpu.h umtx.h

[David Xu]

davidxu     2006-12-20 04:40:39 UTC

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      cpu_switch.S genassym.c machdep.c 
    sys/i386/i386        genassym.c machdep.c swtch.s 
    sys/ia64/ia64        machdep.c 
    sys/kern             kern_umtx.c 
    sys/sys              pcpu.h umtx.h 
  Log:
  Add a lwpid field into per-cpu structure, the lwpid represents current
  running thread's id on each cpu. This allow us to add in-kernel adaptive
  spin for user level mutex. While spinning in user space is possible,
  without correct thread running state exported from kernel, it hardly
  can be implemented efficiently without wasting cpu cycles, however
  exporting thread running state unlikely will be implemented soon as
  it has to design and stablize interfaces. This implementation is
  transparent to user space, it can be disabled dynamically. With this
  change, mutex ping-pong program's performance is improved massively on
  SMP machine. performance of mysql super-smack select benchmark is increased
  about 7% on Intel dual dual-core2 Xeon machine, it indicates on systems
  which have bunch of cpus and system-call overhead is low (athlon64, opteron,
  and core-2 are known to be fast), the adaptive spin does help performance.
  
  Added sysctls:
      kern.threads.umtx_dflt_spins
          if the sysctl value is non-zero, a zero umutex.m_spincount will
          cause the sysctl value to be used a spin cycle count.
      kern.threads.umtx_max_spins
          the sysctl sets upper limit of spin cycle count.
  
  Tested on: Athlon64 X2 3800+, Dual Xeon 5130
  
  Revision  Changes    Path
  1.155     +5 -3      src/sys/amd64/amd64/cpu_switch.S
  1.160     +2 -0      src/sys/amd64/amd64/genassym.c
  1.667     +1 -0      src/sys/amd64/amd64/machdep.c
  1.156     +2 -0      src/sys/i386/i386/genassym.c
  1.646     +1 -0      src/sys/i386/i386/machdep.c
  1.153     +2 -0      src/sys/i386/i386/swtch.s
  1.214     +3 -0      src/sys/ia64/ia64/machdep.c
  1.58      +70 -0     src/sys/kern/kern_umtx.c
  1.20      +1 -0      src/sys/sys/pcpu.h
  1.28      +2 -1      src/sys/sys/umtx.h