diff options
| author | Wanpeng Li <[email protected]> | 2020-09-10 17:50:41 +0800 |
|---|---|---|
| committer | Paolo Bonzini <[email protected]> | 2020-09-28 07:57:10 -0400 |
| commit | 010fd37fddf659ea7525b1191381e6f8c3ccab14 (patch) | |
| tree | fb912e929c3e402bbd3e73ff706b6b616e4b6d5d /tools/perf/scripts/python/flamegraph.py | |
| parent | 68ca7663c75b099539fe675fc5387dee44d3a6cc (diff) | |
KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns
All the checks in lapic_timer_int_injected(), __kvm_wait_lapic_expire(), and
these function calls waste cpu cycles when the timer mode is not tscdeadline.
We can observe ~1.3% world switch time overhead by kvm-unit-tests/vmexit.flat
vmcall testing on AMD server. This patch reduces the world switch latency
caused by timer_advance_ns feature when the timer mode is not tscdeadline by
simpling move the check against apic->lapic_timer.expired_tscdeadline much
earlier.
Signed-off-by: Wanpeng Li <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/flamegraph.py')
0 files changed, 0 insertions, 0 deletions