On Wed, 2015-05-06 at 03:49 +0200, Mike Galbraith wrote:
> On Mon, 2015-05-04 at 22:54 -0700, Paul E. McKenney wrote:
>
> > You have RCU_FAST_NO_HZ=y, correct? Could you please try measuring with
> > RCU_FAST_NO_HZ=n?
>
> FWIW, the syscall numbers I posted were RCU_FAST_NO_HZ=n. (I didn't
> profile to see where costs lie though)
(did that)
100000000 * stat() on isolated cpu
NO_HZ_FULL off inactive housekeeper nohz_full
real 0m14.266s 0m14.367s 0m20.427s 0m27.921s
user 0m1.756s 0m1.553s 0m1.976s 0m10.447s
sys 0m12.508s 0m12.769s 0m18.400s 0m17.464s
(real) 1.000 1.007 1.431 1.957
inactive housekeeper
nohz_full
----------------------------------------------------------------------------------------------------------------------------------------------
7.61% [.] __xstat64 11.12% [k]
context_tracking_exit 7.41% [k] context_tracking_exit
7.04% [k] system_call 6.18% [k]
context_tracking_enter 6.02% [k] native_sched_clock
6.96% [k] copy_user_enhanced_fast_string 5.18% [.] __xstat64
4.69% [k] rcu_eqs_enter_common.isra.37
6.57% [k] path_init 4.89% [k] system_call
4.35% [k] _raw_spin_lock
5.92% [k] system_call_after_swapgs 4.84% [k]
copy_user_enhanced_fast_string 4.30% [k] context_tracking_enter
5.44% [k] lockref_put_return 4.46% [k] path_init
4.25% [k] kmem_cache_alloc
4.69% [k] link_path_walk 4.30% [k]
system_call_after_swapgs 4.14% [.] __xstat64
4.47% [k] lockref_get_not_dead 4.12% [k] kmem_cache_free
3.89% [k] rcu_eqs_exit_common.isra.38
4.46% [k] kmem_cache_free 3.78% [k] link_path_walk
3.50% [k] system_call
4.20% [k] kmem_cache_alloc 3.62% [k]
lockref_put_return 3.48% [k] copy_user_enhanced_fast_string
4.09% [k] cp_new_stat 3.43% [k] kmem_cache_alloc
3.02% [k] system_call_after_swapgs
3.38% [k] vfs_getattr_nosec 2.95% [k]
lockref_get_not_dead 2.97% [k] kmem_cache_free
2.82% [k] vfs_fstatat 2.87% [k] cp_new_stat
2.88% [k] lockref_put_return
2.60% [k] user_path_at_empty 2.62% [k]
syscall_trace_leave 2.61% [k] link_path_walk
2.47% [k] path_lookupat 1.91% [k] vfs_getattr_nosec
2.58% [k] path_init
2.14% [k] strncpy_from_user 1.89% [k]
syscall_trace_enter_phase1 2.15% [k] lockref_get_not_dead
2.11% [k] getname_flags 1.77% [k] path_lookupat
2.04% [k] cp_new_stat
2.10% [k] generic_fillattr 1.67% [k] complete_walk
1.89% [k] generic_fillattr
2.05% [.] main 1.65% [k] vfs_fstatat
1.67% [k] syscall_trace_leave
1.89% [k] complete_walk 1.56% [k] generic_fillattr
1.59% [k] vfs_getattr_nosec
1.73% [k] generic_permission 1.55% [k]
user_path_at_empty 1.49% [k] get_vtime_delta
1.50% [k] system_call_fastpath 1.54% [k] strncpy_from_user
1.32% [k] user_path_at_empty
1.37% [k] legitimize_mnt 1.53% [k] getname_flags
1.30% [k] syscall_trace_enter_phase1
1.30% [k] dput 1.46% [k] legitimize_mnt
1.21% [k] rcu_eqs_exit
1.26% [k] putname 1.34% [.] main
1.21% [k] vfs_fstatat
1.19% [k] path_put 1.32% [k] int_with_check
1.18% [k] path_lookupat
1.18% [k] filename_lookup 1.28% [k]
generic_permission 1.15% [k] getname_flags
1.01% [k] SYSC_newstat 1.16% [k] int_very_careful
1.03% [k] strncpy_from_user
0.96% [k] mntput_no_expire 1.04% [k] putname
1.01% [k] account_system_time
0.79% [k] path_cleanup 0.94% [k] dput
1.00% [k] complete_walk
0.79% [k] mntput 0.91% [k]
context_tracking_user_exit 0.99% [k] vtime_account_user
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