Rewrite the "timers" in memcached?

[Trond Norbye]

Hi,

Memcached currently use timers in libevent to keep the "current time"  
variable up to date (and to run deferred deletes every 5. seconds).  
These timers are added to the main-base used by thread 0, so that  
thread 0 will get these timer-callbacks. This sounds like a good idea,  
but there is one problem with this. Libevent will read out the system  
time _every time_ it will look for new IO-requests (in order to notify  
underlaying IO subsystem for how long it should wait for IO-requests).

I created a small prototype today that creates a "maintenance-thread"  
whose sole purpose is to update the "clock" and run deferred deletes,  
and hence remove all of the clock_gettime-calls from libevent.

So I guess my questions is: What is the status of the single-threaded  
version? Should my patch support both the singlethreaded version  
(meaning that I have to keep the old version), or should I just post a  
patch that use a dedicated thread for timers?

Trond