Memcached缓慢获取，CPU使用率高

I've got a memcached instance running on a machine to take the stress of the database. Currently there are about 350 requests per second via PHP, which should be perfectly doable according to the memcached docs, but I'm seeing ridiculously slow get() times. Averaging around 60 ms, with spikes in both ways (0.1 ms and 250 ms).I've got a memcached instance running on a mach