Alex Thorlton noticed that some massivly threaded workloads work poorly, if THP enabled. This patchset fixes this by introducing split page table lock for PMD tables. hugetlbfs is not covered yet. This patchset is based on work by Naoya Horiguchi. Changes: v2: - reuse CONFIG_SPLIT_PTLOCK_CPUS for PMD split lock; - s/huge_pmd_lock/pmd_lock/g; - assume pgtable_pmd_page_ctor() can fail; - fix format line in task_mem() for VmPTE; Benchmark (from Alex): ftp://shell.sgi.com/collect/appsx_test/pthread_test.tar.gz Run on 4 socket Westmere with 128 GiB of RAM. THP off: -------- Performance counter stats for './thp_pthread -C 0 -m 0 -c 80 -b 100g' (5 runs): 1738259.808012 task-clock # 47.571 CPUs utilized ( +- 9.49% ) 147,359 context-switches # 0.085 K/sec ( +- 9.67% ) 14 cpu-migrations # 0.000 K/sec ( +- 13.25% ) 24,410,139 page-faults # 0.014 M/sec ( +- 0.00% ) 4,149,037,526,252 cycles # 2.387 GHz ( +- 9.50% ) 3,649,839,735,027 stalled-cycles-frontend # 87.97% frontend cycles idle ( +- 6.60% ) 2,455,558,969,567 stalled-cycles-backend # 59.18% backend cycles idle ( +- 22.92% ) 1,434,961,518,604 instructions # 0.35 insns per cycle # 2.54 stalled cycles per insn ( +- 92.86% ) 241,472,020,951 branches # 138.916 M/sec ( +- 91.72% ) 84,022,172 branch-misses # 0.03% of all branches ( +- 3.16% ) 36.540185552 seconds time elapsed ( +- 18.36% ) THP on, no patchset: -------------------- Performance counter stats for './thp_pthread -C 0 -m 0 -c 80 -b 100g' (5 runs): 2528378.966949 task-clock # 50.715 CPUs utilized ( +- 11.86% ) 214,063 context-switches # 0.085 K/sec ( +- 11.94% ) 19 cpu-migrations # 0.000 K/sec ( +- 22.72% ) 49,226 page-faults # 0.019 K/sec ( +- 0.33% ) 6,034,640,598,498 cycles # 2.387 GHz ( +- 11.91% ) 5,685,933,794,081 stalled-cycles-frontend # 94.22% frontend cycles idle ( +- 7.67% ) 4,414,381,393,353 stalled-cycles-backend # 73.15% backend cycles idle ( +- 2.09% ) 952,086,804,776 instructions # 0.16 insns per cycle # 5.97 stalled cycles per insn ( +- 89.59% ) 166,191,211,974 branches # 65.730 M/sec ( +- 85.52% ) 33,341,022 branch-misses # 0.02% of all branches ( +- 3.90% ) 49.854741504 seconds time elapsed ( +- 14.76% ) THP on, with patchset: ---------------------- echo always > /sys/kernel/mm/transparent_hugepage/enabled Performance counter stats for './thp_pthread -C 0 -m 0 -c 80 -b 100g' (5 runs): 1538763.343568 task-clock # 45.386 CPUs utilized ( +- 7.21% ) 130,469 context-switches # 0.085 K/sec ( +- 7.32% ) 14 cpu-migrations # 0.000 K/sec ( +- 23.58% ) 49,299 page-faults # 0.032 K/sec ( +- 0.15% ) 3,666,748,502,650 cycles # 2.383 GHz ( +- 7.25% ) 3,330,488,035,212 stalled-cycles-frontend # 90.83% frontend cycles idle ( +- 4.70% ) 2,383,357,073,990 stalled-cycles-backend # 65.00% backend cycles idle ( +- 16.06% ) 935,504,610,528 instructions # 0.26 insns per cycle # 3.56 stalled cycles per insn ( +- 91.16% ) 161,466,689,532 branches # 104.933 M/sec ( +- 87.67% ) 22,602,225 branch-misses # 0.01% of all branches ( +- 6.43% ) 33.903917543 seconds time elapsed ( +- 12.57% ) Kirill A. Shutemov (9): mm: rename USE_SPLIT_PTLOCKS to USE_SPLIT_PTE_PTLOCKS mm: convert mm->nr_ptes to atomic_t mm: introduce api for split page table lock for PMD level mm, thp: change pmd_trans_huge_lock() to return taken lock mm, thp: move ptl taking inside page_check_address_pmd() mm, thp: do not access mm->pmd_huge_pte directly mm: convent the rest to new page table lock api mm: implement split page table lock for PMD level x86, mm: enable split page table lock for PMD level arch/arm/mm/fault-armv.c | 6 +- arch/s390/mm/pgtable.c | 12 +-- arch/sparc/mm/tlb.c | 12 +-- arch/x86/Kconfig | 4 + arch/x86/include/asm/pgalloc.h | 11 ++- arch/x86/xen/mmu.c | 6 +- fs/proc/task_mmu.c | 17 ++-- include/linux/huge_mm.h | 17 ++-- include/linux/mm.h | 52 ++++++++++- include/linux/mm_types.h | 18 ++-- kernel/fork.c | 6 +- mm/Kconfig | 3 + mm/huge_memory.c | 201 ++++++++++++++++++++++++----------------- mm/memcontrol.c | 10 +- mm/memory.c | 21 +++-- mm/migrate.c | 7 +- mm/mmap.c | 3 +- mm/mprotect.c | 4 +- mm/oom_kill.c | 6 +- mm/pgtable-generic.c | 16 ++-- mm/rmap.c | 13 +-- 21 files changed, 276 insertions(+), 169 deletions(-) -- 1.8.4.rc3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
