diff options
| author | Andrei Vagin <avagin@google.com> | 2019-11-18 14:55:30 -0800 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-11-18 14:56:49 -0800 |
| commit | 26b3341b9ae08bb72971d5465c77e6c8db82c996 (patch) | |
| tree | 17948f8ebd48b6354c96c2923c32fa8e146abf60 | |
| parent | 235a96cab15e64c69fbbdce03c9bb4eb2c30b0d5 (diff) | |
platform/ptrace: use host.GetCPU instead of the getcpu syscall
This should save ~200ns from switchToApp (on ptrace too). // mpratt
PiperOrigin-RevId: 281159895
| -rw-r--r-- | pkg/sentry/platform/ptrace/BUILD | 1 | ||||
| -rw-r--r-- | pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go | 21 |
2 files changed, 4 insertions, 18 deletions
diff --git a/pkg/sentry/platform/ptrace/BUILD b/pkg/sentry/platform/ptrace/BUILD index ebcc8c098..0df8cfa0f 100644 --- a/pkg/sentry/platform/ptrace/BUILD +++ b/pkg/sentry/platform/ptrace/BUILD @@ -28,6 +28,7 @@ go_library( "//pkg/procid", "//pkg/seccomp", "//pkg/sentry/arch", + "//pkg/sentry/hostcpu", "//pkg/sentry/platform", "//pkg/sentry/platform/interrupt", "//pkg/sentry/platform/safecopy", diff --git a/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go b/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go index de6783fb0..2e6fbe488 100644 --- a/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go +++ b/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go @@ -25,6 +25,7 @@ import ( "golang.org/x/sys/unix" "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/hostcpu" ) // maskPool contains reusable CPU masks for setting affinity. Unfortunately, @@ -49,20 +50,6 @@ func unmaskAllSignals() syscall.Errno { return errno } -// getCPU gets the current CPU. -// -// Precondition: the current runtime thread should be locked. -func getCPU() (uint32, error) { - var cpu uintptr - if _, _, errno := syscall.RawSyscall( - unix.SYS_GETCPU, - uintptr(unsafe.Pointer(&cpu)), - 0, 0); errno != 0 { - return 0, errno - } - return uint32(cpu), nil -} - // setCPU sets the CPU affinity. func (t *thread) setCPU(cpu uint32) error { mask := maskPool.Get().([]uintptr) @@ -93,10 +80,8 @@ func (t *thread) setCPU(cpu uint32) error { // // Precondition: the current runtime thread should be locked. func (t *thread) bind() { - currentCPU, err := getCPU() - if err != nil { - return - } + currentCPU := hostcpu.GetCPU() + if oldCPU := atomic.SwapUint32(&t.cpu, currentCPU); oldCPU != currentCPU { // Set the affinity on the thread and save the CPU for next // round; we don't expect CPUs to bounce around too frequently. |