On Sat, 2005-01-08 at 00:37 +0100, Alfio Puglisi wrote:
In my experience, usleep() cannot be shorter than a single time slice fromt the Linux scheduler, which for 2.6 kernels should be 1 millisecond.
So that code is waiting up to 200 milliseconds, with negligible CPU overhead, unless of course PHP does things differently. But to sleep less than a timeslice you need to busy sleep, so the CPU would be taxed at 100% in that case.
Alfio,
thanks for clearing that up. I set up the squids Friday evening, purges have been enabled to all three french machines since then without making a difference. Right now the first real traffic is starting to hit them, with dns managed by Mark using GeoDNS (sends fr.wikipedia.org visitors to the french squids if they have a french ip).
Stats: http://bleuenn.wikimedia.org:8080/ganglia/?c=Paris% 20cluster&m=&r=hour&s=descending&hc=4