ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
range of input addresses. This series add support for this feature.
I tested this feature on a FPGA machine whose cpus support the tlbi range.
As the page num increases, the performance is improved significantly. When
page num = 256, the performance is improved by about 10 times.
Below is the test data when the stride = PTE:
[page num] [classic] [tlbi range]
1 16051 13524
2 11366 11146
3 11582 12171
4 11694 11101
5 12138 12267
6 12290 11105
7 12400 12002
8 12837 11097
9 14791 12140
10 15461 11087
16 18233 11094
32 26983 11079
64 43840 11092
128 77754 11098
256 145514 11089
512 280932 11111
See more details in:
https://lore.kernel.org/linux-arm-kernel/504c7588-97e5-e014-fca0-c5511ae0d...@huawei.com/
--
ChangeList:
v5:
- rebase this series on Linux 5.8-rc4.
- remove the __TG macro.
- move the odd range_pages check into loop.
v4:
combine the __flush_tlb_range() and the __directly into the same function
with a single loop for both.
v3:
rebase this series on Linux 5.7-rc1.
v2:
Link: https://lkml.org/lkml/2019/11/11/348
Zhenyu Ye (2):
arm64: tlb: Detect the ARMv8.4 TLBI RANGE feature
arm64: tlb: Use the TLBI RANGE feature in arm64
arch/arm64/include/asm/cpucaps.h | 3 +-
arch/arm64/include/asm/sysreg.h | 3 +
arch/arm64/include/asm/tlbflush.h | 101 +++++++++++++++++++++++++-----
arch/arm64/kernel/cpufeature.c | 10 +++
4 files changed, 102 insertions(+), 15 deletions(-)
--
2.19.1
