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Etienne PerotandgVisor bot
640a42e63c
This is part of a series of changes to add metric charts in performance benchmarks. This change is meant to do three things: - Remove the interface indirection from the Prometheus library, which is performance-critical due to its use in writing out profiling metrics (although the runsc metric server also benefits from this too). - Use a `StringWriter`-like writer contract, to avoid needless casting between strings and bytes within the Prometheus library. The library only ever needs to deal with strings, so it is up to callers to do the conversion to bytes if they need to (which the runsc metric-server does). - Avoid buffer allocations in the metric server when each snapshot is larger than the buffer size. Instead, buffers are saved and reused. PiperOrigin-RevId: 630500004
84 lines
2.8 KiB
Go
84 lines
2.8 KiB
Go
// Copyright 2023 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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package metricserver
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import (
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"errors"
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"net/http"
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"runtime"
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"runtime/pprof"
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"strconv"
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"time"
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"gvisor.dev/gvisor/pkg/log"
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)
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// profileCPU returns a CPU profile over HTTP.
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func (m *metricServer) profileCPU(w *httpResponseWriter, req *http.Request) httpResult {
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// Time to finish up profiling and flush out the results to the client.
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const finishProfilingBuffer = 250 * time.Millisecond
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m.mu.Lock()
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if m.shuttingDown {
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m.mu.Unlock()
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return httpResult{http.StatusServiceUnavailable, errors.New("server is shutting down already")}
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}
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m.mu.Unlock()
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w.WriteHeader(http.StatusOK)
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if err := pprof.StartCPUProfile(w); err != nil {
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// We cannot return this as an error, because we've already sent the HTTP 200 OK status.
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log.Warningf("Failed to start recording CPU profile: %v", err)
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return httpOK
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}
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deadline := time.Now().Add(httpTimeout - finishProfilingBuffer)
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if seconds, err := strconv.Atoi(req.URL.Query().Get("seconds")); err == nil && time.Duration(seconds)*time.Second < httpTimeout {
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deadline = time.Now().Add(time.Duration(seconds) * time.Second)
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} else if ctxDeadline, hasDeadline := req.Context().Deadline(); hasDeadline {
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deadline = ctxDeadline.Add(-finishProfilingBuffer)
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}
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log.Infof("Profiling CPU until %v...", deadline)
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var wasInterrupted bool
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select {
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case <-time.After(time.Until(deadline)):
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wasInterrupted = false
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case <-req.Context().Done():
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wasInterrupted = true
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}
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pprof.StopCPUProfile()
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if wasInterrupted {
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log.Warningf("Profiling CPU interrupted.")
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} else {
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log.Infof("Profiling CPU done.")
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}
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return httpOK
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}
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// profileHeap returns a heap profile over HTTP.
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func (m *metricServer) profileHeap(w *httpResponseWriter, req *http.Request) httpResult {
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m.mu.Lock()
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if m.shuttingDown {
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m.mu.Unlock()
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return httpResult{http.StatusServiceUnavailable, errors.New("server is shutting down already")}
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}
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m.mu.Unlock()
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w.WriteHeader(http.StatusOK)
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runtime.GC() // Run GC just before looking at the heap to get a clean view.
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if err := pprof.Lookup("heap").WriteTo(w, 0); err != nil {
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// We cannot return this as an error, because we've already sent the HTTP 200 OK status.
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log.Warningf("Failed to record heap profile: %v", err)
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}
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return httpOK
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}
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