Re: kernbench on 512p

Paul E. McKenney
2004-08-19T23:42:18Z

On Thu, Aug 19, 2004 at 05:24:04PM -0400, Jesse Barnes wrote:
> On Thursday, August 19, 2004 5:11 pm, Jesse Barnes wrote:
> > The output is attached (my mailer insists on wrapping it if I inline it).
> > I used 'lockstat -w'.
>
> The highlights:
>
> nw spin rjct lock & function
> 19.0% 81.0% 0% dcache_lock
> 3.3% 96.7% 0% d_alloc+0x270
> 2.7% 97.3% 0% d_delete+0x40
> 18.3% 81.7% 0% d_instantiate+0x90
> 4.7% 95.3% 0% d_move+0x60
> 34.6% 65.4% 0% d_rehash+0xe0
> 19.1% 80.9% 0% dput+0x40
> 10.5% 89.5% 0% link_path_walk+0xef0
> 0% 100% 0% sys_getcwd+0x210
>
> 41.4% 58.6% 0% rcu_state
> 61.3% 38.7% 0% __rcu_process_callbacks+0x260
> 41.4% 58.6% 0% rcu_check_quiescent_state+0xf0
>
> So it looks like the dcache lock is the biggest problem on this system with
> this load. And although the rcu stuff has improved tremendously for this
> system, it's still highly contended.

Was this run using all of Manfred's RCU patches? If not, it would be
interesting to see what you get with full RCU_HUGE patchset.

Thanx, Paul