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| author | Nicholas Piggin <npiggin@gmail.com> | 2018-05-17 16:59:10 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2018-05-18 15:38:23 +1000 |
| commit | b7557451475d747740bc1598045bd273ece80ab0 (patch) | |
| tree | 95e5efbb1667f88712274c0b3152dff2699b2b77 /arch/powerpc/kvm/book3s_64_mmu_hv.c | |
| parent | f19d1f367a506bc645f8d6695942b8873fc82c84 (diff) | |
| download | linux-b7557451475d747740bc1598045bd273ece80ab0.tar.gz linux-b7557451475d747740bc1598045bd273ece80ab0.tar.bz2 linux-b7557451475d747740bc1598045bd273ece80ab0.zip | |
KVM: PPC: Book3S HV: Lockless tlbie for HPT hcalls
tlbies to an LPAR do not have to be serialised since POWER4/PPC970,
after which the MMU_FTR_LOCKLESS_TLBIE feature was introduced to
avoid tlbie locking.
Since commit c17b98cf6028 ("KVM: PPC: Book3S HV: Remove code for
PPC970 processors"), KVM no longer supports processors that do not
have this feature, so the tlbie locking can be removed completely.
A sanity check for the feature is put in kvmppc_mmu_hv_init.
Testing was done on a POWER9 system in HPT mode, with a -smp 32 guest
in HPT mode. 32 instances of the powerpc fork benchmark from selftests
were run with --fork, and the results measured.
Without this patch, total throughput was about 13.5K/sec, and this is
the top of the host profile:
74.52% [k] do_tlbies
2.95% [k] kvmppc_book3s_hv_page_fault
1.80% [k] calc_checksum
1.80% [k] kvmppc_vcpu_run_hv
1.49% [k] kvmppc_run_core
After this patch, throughput was about 51K/sec, with this profile:
21.28% [k] do_tlbies
5.26% [k] kvmppc_run_core
4.88% [k] kvmppc_book3s_hv_page_fault
3.30% [k] _raw_spin_lock_irqsave
3.25% [k] gup_pgd_range
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index a670fa5fbe50..37cd6434d1c8 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -272,6 +272,9 @@ int kvmppc_mmu_hv_init(void) if (!cpu_has_feature(CPU_FTR_HVMODE)) return -EINVAL; + if (!mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE)) + return -EINVAL; + /* POWER7 has 10-bit LPIDs (12-bit in POWER8) */ host_lpid = mfspr(SPRN_LPID); rsvd_lpid = LPID_RSVD; |