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-rw-r--r--pkg/sentry/time/sampler_unsafe.go56
1 files changed, 56 insertions, 0 deletions
diff --git a/pkg/sentry/time/sampler_unsafe.go b/pkg/sentry/time/sampler_unsafe.go
new file mode 100644
index 000000000..e76180217
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+++ b/pkg/sentry/time/sampler_unsafe.go
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+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package time
+
+import (
+ "syscall"
+ "unsafe"
+)
+
+// syscallTSCReferenceClocks is the standard referenceClocks, collecting
+// samples using CLOCK_GETTIME and RDTSC.
+type syscallTSCReferenceClocks struct {
+ tscCycleClock
+}
+
+// Sample implements sampler.Sample.
+func (syscallTSCReferenceClocks) Sample(c ClockID) (sample, error) {
+ var s sample
+
+ s.before = Rdtsc()
+
+ // Don't call clockGettime to avoid a call which may call morestack.
+ var ts syscall.Timespec
+ _, _, e := syscall.RawSyscall(syscall.SYS_CLOCK_GETTIME, uintptr(c), uintptr(unsafe.Pointer(&ts)), 0)
+ if e != 0 {
+ return sample{}, e
+ }
+
+ s.after = Rdtsc()
+ s.ref = ReferenceNS(ts.Nano())
+
+ return s, nil
+}
+
+// clockGettime calls SYS_CLOCK_GETTIME, returning time in nanoseconds.
+func clockGettime(c ClockID) (ReferenceNS, error) {
+ var ts syscall.Timespec
+ _, _, e := syscall.RawSyscall(syscall.SYS_CLOCK_GETTIME, uintptr(c), uintptr(unsafe.Pointer(&ts)), 0)
+ if e != 0 {
+ return 0, e
+ }
+
+ return ReferenceNS(ts.Nano()), nil
+}