diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2024-02-21 20:08:31 +1000 |
|---|---|---|
| committer | Nicholas Piggin <npiggin@gmail.com> | 2024-05-24 08:57:50 +1000 |
| commit | c700b5e162208a0fa4211fc6d9dab271b1342640 (patch) | |
| tree | 794e2bd36806c77269fc4e3dff93e7f1d32fdbf3 /hw/ppc/pegasos2.c | |
| parent | 70581940cabcc51b329652becddfbc6a261b1b83 (diff) | |
spapr: avoid overhead of finding vhyp class in critical operations
PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like
interrupts and TLB misses and is quite costly. Running the
kvm-unit-tests sieve program with radix MMU enabled thrashes the TCG
TLB and spends a lot of time in TLB and page table walking code. The
test takes 67 seconds to complete with a lot of time being spent in
code related to finding the vhyp class:
12.01% [.] g_str_hash
8.94% [.] g_hash_table_lookup
8.06% [.] object_class_dynamic_cast
6.21% [.] address_space_ldq
4.94% [.] __strcmp_avx2
4.28% [.] tlb_set_page_full
4.08% [.] address_space_translate_internal
3.17% [.] object_class_dynamic_cast_assert
2.84% [.] ppc_radix64_xlate
Keep a pointer to the class and avoid this lookup. This reduces the
execution time to 40 seconds.
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Diffstat (limited to 'hw/ppc/pegasos2.c')
| -rw-r--r-- | hw/ppc/pegasos2.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/hw/ppc/pegasos2.c b/hw/ppc/pegasos2.c index 04d6decb2b..c22e8b336d 100644 --- a/hw/ppc/pegasos2.c +++ b/hw/ppc/pegasos2.c @@ -400,6 +400,7 @@ static void pegasos2_machine_reset(MachineState *machine, ShutdownCause reason) machine->fdt = fdt; pm->cpu->vhyp = PPC_VIRTUAL_HYPERVISOR(machine); + pm->cpu->vhyp_class = PPC_VIRTUAL_HYPERVISOR_GET_CLASS(pm->cpu->vhyp); } enum pegasos2_rtas_tokens { |