Hi All,
this is the fairlock patchset. You can apply them and build successfully.
patches are based on 4.8-rc4.
qspinlock can avoid waiter starved issue. It has about the same speed in
single-thread and it can be much faster in high contention situations
especially when the spinlock is embedded within the data structure to be
protected.
v6 -> v7:
rebase onto 4.8-rc4
no changelog anymore, sorry for that. I hope there is a very careful review.
Todo:
we can save one function call overhead. As we can use feature-fixup to patch
the binary code. Currently there is pv_lock_ops->lock(lock) and ->unlock(lock) to acquire/release the lock.
some benchmark result below
perf bench
these numbers are ops per sec, So the higher the better.
*******************************************
on pSeries with 32 vcpus, 32Gb memory, pHyp.
------------------------------------------------------------------------------------
test case | pv-qspinlock | qspinlock | current-spinlock
------------------------------------------------------------------------------------
futex hash | 618572 | 552332 | 553788
futex lock-pi | 364 | 364 | 364
sched pipe | 78984 | 76060 | 81454
------------------------------------------------------------------------------------
unix bench:
these numbers are scores, So the higher the better.
************************************************
on PowerNV with 16 cores(cpus) (smt off), 32Gb memory:
-------------
pv-qspinlock and qspinlock have very similar results because pv-qspinlock use native version
which is only having one callback overhead
------------------------------------------------------------------------------------
test case | pv-qspinlock and qspinlock | current-spinlock
------------------------------------------------------------------------------------
Execl Throughput 761.1 761.4
File Copy 1024 bufsize 2000 maxblocks 1259.8 1286.6
File Copy 256 bufsize 500 maxblocks 782.2 790.3
File Copy 4096 bufsize 8000 maxblocks 2741.5 2817.4
Pipe Throughput 1063.2 1036.7
Pipe-based Context Switching 284.7 281.1
Process Creation 679.6 649.1
Shell Scripts (1 concurrent) 1933.2 1922.9
Shell Scripts (8 concurrent) 5003.3 4899.8
System Call Overhead 900.6 896.8
==========================
System Benchmarks Index Score 1139.3 1133.0
--------------------------------------------------------------------------- ---------
*******************************************
on pSeries with 32 vcpus, 32Gb memory, pHyp.
------------------------------------------------------------------------------------
test case | pv-qspinlock | qspinlock | current-spinlock
------------------------------------------------------------------------------------
Execl Throughput 877.1 891.2 872.8
File Copy 1024 bufsize 2000 maxblocks 1390.4 1399.2 1395.0
File Copy 256 bufsize 500 maxblocks 882.4 889.5 881.8
File Copy 4096 bufsize 8000 maxblocks 3112.3 3113.4 3121.7
Pipe Throughput 1095.8 1162.6 1158.5
Pipe-based Context Switching 194.9 192.7 200.7
Process Creation 518.4 526.4 509.1
Shell Scripts (1 concurrent) 1401.9 1413.9 1402.2
Shell Scripts (8 concurrent) 3215.6 3246.6 3229.1
System Call Overhead 833.2 892.4 888.1
====================================
System Benchmarks Index Score 1033.7 1052.5 1047.8
------------------------------------------------------------------------------------
******************************************
on pSeries with 32 vcpus, 16Gb memory, KVM.
------------------------------------------------------------------------------------
test case | pv-qspinlock | qspinlock | current-spinlock
------------------------------------------------------------------------------------
Execl Throughput 497.4 518.7 497.8
File Copy 1024 bufsize 2000 maxblocks 1368.8 1390.1 1343.3
File Copy 256 bufsize 500 maxblocks 857.7 859.8 831.4
File Copy 4096 bufsize 8000 maxblocks 2851.7 2838.1 2785.5
Pipe Throughput 1221.9 1265.3 1250.4
Pipe-based Context Switching 529.8 578.1 564.2
Process Creation 408.4 421.6 287.6
Shell Scripts (1 concurrent) 1201.8 1215.3 1185.8
Shell Scripts (8 concurrent) 3758.4 3799.3 3878.9
System Call Overhead 1008.3 1122.6 1134.2
=====================================
System Benchmarks Index Score 1072.0 1108.9 1050.6
------------------------------------------------------------------------------------
Pan Xinhui (6):
pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock
powerpc/qspinlock: powerpc support qspinlock
powerpc: pseries/Kconfig: Add qspinlock build config
powerpc: lib/locks.c: Add cpu yield/wake helper function
powerpc/pv-qspinlock: powerpc support pv-qspinlock
powerpc: pSeries: Add pv-qspinlock build config/make
arch/powerpc/include/asm/qspinlock.h | 93 +++++++++++++
arch/powerpc/include/asm/qspinlock_paravirt.h | 36 +++++
.../powerpc/include/asm/qspinlock_paravirt_types.h | 13 ++
arch/powerpc/include/asm/spinlock.h | 35 +++--
arch/powerpc/include/asm/spinlock_types.h | 4 +
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/paravirt.c | 153 +++++++++++++++++++++
arch/powerpc/lib/locks.c | 122 ++++++++++++++++
arch/powerpc/platforms/pseries/Kconfig | 9 ++
arch/powerpc/platforms/pseries/setup.c | 5 +
kernel/locking/qspinlock_paravirt.h | 2 +-
11 files changed, 459 insertions(+), 14 deletions(-)
create mode 100644 arch/powerpc/include/asm/qspinlock.h
create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h
create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt_types.h
create mode 100644 arch/powerpc/kernel/paravirt.c
--
2.4.11
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