On Tuesday 07 October 2008 07:44:00 am 邱剑 wrote: > Hi, folks, > > I did kernel profiling when a single thread client sends UDP packets to a > single thread server on the same machine. > > In the output kernel profile, the first few kernel functions that consumes > the most CPU time are listed below: > > granularity: each sample hit covers 16 byte(s) for 0.01% of 25.68 seconds > > % cumulative self self total > time seconds seconds calls ms/call ms/call name > 42.4 10.88 10.88 0 100.00% __mcount [1] > 36.1 20.14 9.26 17937541 0.00 0.00 spinlock_exit [4] > 4.2 21.22 1.08 3145728 0.00 0.00 in_cksum_skip [40] > 1.8 21.68 0.45 7351987 0.00 0.00 generic_copyin [43] > 1.1 21.96 0.29 3146028 0.00 0.00 generic_copyout [48] > 1.0 22.21 0.24 2108904 0.00 0.00 Xint0x80_syscall [3] > 0.8 22.42 0.21 6292131 0.00 0.00 uma_zalloc_arg [46] > 0.8 22.62 0.20 1048576 0.00 0.00 soreceive_generic [9] > > It is very strange that spinlock_exit consumes over 36% CPU time while it > seems a very simple function.
It's because the intr_restore() re-enables interrupts and the resulting time spent executing the handlers for any pending interrupts are attributed to spinlock_exit(). -- John Baldwin _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
