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java - Is it possible to detect the time difference between the moment an epoll is generated by the kernel and the moment the Sun JVM reads it? -
i.e. time = voltage hits nic; time b = selector java nio package able select socket channel i/o.
use so_timestamp , find nic supports timestamps , 1 supports timestamps better millisecond resolution. should have chance if can java read incoming cmsg
ancillary data.
without hardware support packets going tagged kernel low resolution unstable timer.
(edit #1) example code in c requiring 2.6.30 or newer kernel think:
http://www.mjmwired.net/kernel/documentation/networking/timestamping/timestamping.c
(edit #2) example code determine kernel user-space latency in c:
http://vilimpoc.org/research/ku-latency/
(edit #3) recommend following j-owamp project dependent upon high resolution timers , packet latency testing. owamp team have been pushing linux kernel team better so_timestamp support.
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