cvs commit: src/share/man/man9 locking.9 rmlock.9 src/sys/conf files src/sys/kern kern_rmlock.c subr_lock.c subr_pcpu.c subr_smp.c src/sys/sys _rmlock.h lock.h pcpu.h rmlock.h smp.h

Julian Elischer julian at
Sun Nov 25 08:30:24 PST 2007

Darren Reed wrote:
> Stephan Uphoff wrote:
>> ups         2007-11-08 14:47:55 UTC
>>   FreeBSD src repository
>>   Modified files:
>>     share/man/man9       locking.9     sys/conf             files     
>> sys/kern             subr_lock.c subr_pcpu.c subr_smp.c     
>> sys/sys              lock.h pcpu.h smp.h   Added files:
>>     share/man/man9       rmlock.9     sys/kern             
>> kern_rmlock.c     sys/sys              _rmlock.h rmlock.h   Log:
>>   Initial checkin for rmlock (read mostly lock) a multi reader single 
>> writer
>>   lock optimized for almost exclusive reader access. (see also rmlock.9)
> Is there a white paper or other documentation around somewhere that
> discusses the benefits/tradeoffs with using rmlock vs rwlock?
> For example, how long can a write be delayed if there are lots of reads
> being executed?  What sort of performance penalty does the write
> suffer as a consequence of this vs rwlock, if any?
> At what percentage of read vs write operations does it become better
> to use rmlock vs rwlock?
> Cheers,
> Darren

locking(9) is supposed to give an overview..
(but needs input from people to improve it)

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