Hello, I try to analyze the lock contention in the linux FS, so I enable lockstats in the kernel. But I have some troubles to understand the result in lockstats. When I read 4GB data randomly from a file on a ramdisk with 8 threads (I have 8 cores), and it takes 21 seconds. The most contended lock is class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total &(&mapping->tree_lock)->rlock 104380 104615 0 0 61705.23 169228 2862470 0 0 1010557.22 &(&zone->lru_lock)->rlock 1233 1245 0 0 2632.71 21834 255752 0 3.86 402904.1 xtime_lock 722 731 0 0 1916.15 1342 2901 0 0 4812.51 What is unit of the waittime? in nanoseconds? I look into the code of x86, and it seems the clock time the code reads is nanoseconds. But if it's in nanoseconds, the wait time of mapping->tree_lock is very short, only 62us in total? Also, the result shows that there are 104615 contentions out of 2862470 acquisitions. I guess it's not very highly contended. Thanks, Da