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Subject[PATCH 0/5] locking/lockdep: Improve lockdep performance
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Enabling CONFIG_LOCKDEP and other related debug options will greatly
reduce system performance. This patchset aims to reduce the performance
slowdown caused by the lockdep code.

Patch 1 just removes an inline function that wasn't used.

Patches 2 and 3 are minor twists to optimize the code.

Patch 4 makes class->ops a per-cpu counter.

Patch 5 moves the lock_release() call outside of a lock critical section.

Parallel kernel compilation tests (make -j <#cpu>) were performed on
2 different systems:

1) an 1-socket 22-core 44-thread Skylake system
2) a 4-socket 72-core 144-thread Broadwell system

The build times with pre-patch and post-patch debug kernels were:

System Pre-patch Post-patch %Change
------ --------- ---------- -------
1-socket 8m53.9s 8m41.2s -2.4%
4-socket 7m27.0s 5m31.0s -26%

I think it is the last 2 patches that yield most of the performance
improvement.

Waiman Long (5):
locking/lockdep: Remove add_chain_cache_classes()
locking/lockdep: Eliminate redundant irqs check in __lock_acquire()
locking/lockdep: Add a faster path in __lock_release()
locking/lockdep: Make class->ops a percpu counter
locking/lockdep: Call lock_release after releasing the lock

include/linux/lockdep.h | 2 +-
include/linux/rwlock_api_smp.h | 16 +++---
include/linux/spinlock_api_smp.h | 8 +--
kernel/locking/lockdep.c | 120 ++++++++++++---------------------------
4 files changed, 48 insertions(+), 98 deletions(-)

--
1.8.3.1

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