diff options
| -rw-r--r-- | pkg/sentry/time/BUILD | 2 | ||||
| -rw-r--r-- | pkg/sentry/time/sampler.go | 7 | ||||
| -rw-r--r-- | pkg/sentry/time/sampler_amd64.go | 26 | ||||
| -rw-r--r-- | pkg/sentry/time/sampler_arm64.go | 42 | ||||
| -rw-r--r-- | pkg/sentry/time/tsc_arm64.s | 6 |
5 files changed, 76 insertions, 7 deletions
diff --git a/pkg/sentry/time/BUILD b/pkg/sentry/time/BUILD index 362dea76d..202486a1e 100644 --- a/pkg/sentry/time/BUILD +++ b/pkg/sentry/time/BUILD @@ -25,6 +25,8 @@ go_library( "muldiv_arm64.s", "parameters.go", "sampler.go", + "sampler_amd64.go", + "sampler_arm64.go", "sampler_unsafe.go", "seqatomic_parameters_unsafe.go", "tsc_amd64.s", diff --git a/pkg/sentry/time/sampler.go b/pkg/sentry/time/sampler.go index 4ac9c4474..24a47f5d5 100644 --- a/pkg/sentry/time/sampler.go +++ b/pkg/sentry/time/sampler.go @@ -21,13 +21,6 @@ import ( ) const ( - // defaultOverheadTSC is the default estimated syscall overhead in TSC cycles. - // It is further refined as syscalls are made. - defaultOverheadCycles = 1 * 1000 - - // maxOverheadCycles is the maximum allowed syscall overhead in TSC cycles. - maxOverheadCycles = 100 * defaultOverheadCycles - // maxSampleLoops is the maximum number of times to try to get a clock sample // under the expected overhead. maxSampleLoops = 5 diff --git a/pkg/sentry/time/sampler_amd64.go b/pkg/sentry/time/sampler_amd64.go new file mode 100644 index 000000000..9f1b4b2fb --- /dev/null +++ b/pkg/sentry/time/sampler_amd64.go @@ -0,0 +1,26 @@ +// 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. + +//+build amd64 + +package time + +const ( + // defaultOverheadTSC is the default estimated syscall overhead in TSC cycles. + // It is further refined as syscalls are made. + defaultOverheadCycles = 1 * 1000 + + // maxOverheadCycles is the maximum allowed syscall overhead in TSC cycles. + maxOverheadCycles = 100 * defaultOverheadCycles +) diff --git a/pkg/sentry/time/sampler_arm64.go b/pkg/sentry/time/sampler_arm64.go new file mode 100644 index 000000000..4c8d33ae4 --- /dev/null +++ b/pkg/sentry/time/sampler_arm64.go @@ -0,0 +1,42 @@ +// 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. + +//+build arm64 + +package time + +// getCNTFRQ get ARM counter-timer frequency +func getCNTFRQ() TSCValue + +// getDefaultArchOverheadCycles get default OverheadCycles based on +// ARM counter-timer frequency. Usually ARM counter-timer frequency +// is range from 1-50Mhz which is much less than that on x86, so we +// calibrate defaultOverheadCycles for ARM. +func getDefaultArchOverheadCycles() TSCValue { + // estimated the clock frequency on x86 is 1Ghz. + // 1Ghz devided by counter-timer frequency of ARM to get + // frqRatio. defaultOverheadCycles of ARM equals to that on + // x86 devided by frqRatio + cntfrq := getCNTFRQ() + frqRatio := 1000000000 / cntfrq + overheadCycles := (1 * 1000) / frqRatio + return overheadCycles +} + +// defaultOverheadTSC is the default estimated syscall overhead in TSC cycles. +// It is further refined as syscalls are made. +var defaultOverheadCycles = getDefaultArchOverheadCycles() + +// maxOverheadCycles is the maximum allowed syscall overhead in TSC cycles. +var maxOverheadCycles = 100 * defaultOverheadCycles diff --git a/pkg/sentry/time/tsc_arm64.s b/pkg/sentry/time/tsc_arm64.s index da9fa4112..711349fa1 100644 --- a/pkg/sentry/time/tsc_arm64.s +++ b/pkg/sentry/time/tsc_arm64.s @@ -20,3 +20,9 @@ TEXT ·Rdtsc(SB),NOSPLIT,$0-8 WORD $0xd53be040 //MRS CNTVCT_EL0, R0 MOVD R0, ret+0(FP) RET + +TEXT ·getCNTFRQ(SB),NOSPLIT,$0-8 + // Get the virtual counter frequency. + WORD $0xd53be000 //MRS CNTFRQ_EL0, R0 + MOVD R0, ret+0(FP) + RET |