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Etienne PerotandgVisor bot
15e3dd3c3d
Since `arch.Context64` is the only concrete implementation of `arch.Context`, this does not functionally change anything. While `arch.Context64` *can* mean multiple things in the codebase, since the `arch` module uses conditional compilation to create different builds for AMD64 vs ARM64, the `Context64` type is still singular within each possible version this can compile to. This avoids the overhead involved in calling interface functions in Go: https://github.com/teh-cmc/go-internals/blob/master/chapter2_interfaces/README.md#dynamic-dispatch This overhead is particularly painful for functions like `SyscallSaveOrig` which is a no-op on AMD64. On KVM, this reduces syscall latency by 4~5%: ``` name old wall_ns/op new wall_ns/op delta Getpid 602 ± 4% 579 ± 3% -3.94% (p=0.000 n=66+195) GetpidOpt 604 ± 3% 573 ± 3% -5.10% (p=0.000 n=71+194) name old cpu_ns/op new cpu_ns/op delta Getpid 604 ± 5% 581 ± 0% -3.81% (p=0.000 n=75+130) GetpidOpt 604 ± 2% 574 ± 3% -4.95% (p=0.000 n=71+196) ``` PiperOrigin-RevId: 461742893
29 lines
894 B
Go
29 lines
894 B
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build arm64
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// +build arm64
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package platform
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import (
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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)
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// TryCPUIDEmulate always returns false: there is no cpuid.
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func TryCPUIDEmulate(ctx context.Context, mm MemoryManager, ac *arch.Context64) bool {
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return false
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}
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