ru.unix.bsd

 
 - RU.UNIX.BSD ------------------------------------------------------------------
 From : Slawa Olhovchenkov                   2:5030/500     02 Jan 2007  00:45:10
 To : All
 Subject : Вести с полей
 -------------------------------------------------------------------------------- 
 

 
 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
 ... Сэр, я ничего не хочу сказать, но, сэр, мухи... они редко ошибаются, сэр!
 --- GoldED+/BSD 1.1.5
  * Origin:  (2:5030/500)
 
 

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