Re: [RFC] New locking primitive for 2.5

Robert Love
2002-02-08T19:36:56Z

On Fri, 2002-02-08 at 14:21, Alexander Viro wrote:

> Had anyone actually seen lseek() vs. lseek() contention prior to the
> switch to ->i_sem-based variant?

Yes, I did, even on my 2-way.

Additionally, when I posted the remove-bkl-llseek patch, someone from
SGI noted that on a 24-processor NUMA IA-64 machine, _50%_ of machine
time was spent spinning on the BKL in llseek-intense operations.

The bkl is not held for a long time, but it is acquired often, and there
are definitely workloads that show a big hit with the BKL in there.

Robert Love