pkg/profile: Replace gzip package to reduce allocs

[marselester]

A drop-in replacement for gzip has impressively low allocs with decent speed/compression klauspost/compress#216. See, gzip related code no longer shows up in the pprof top20.

Details

(pprof) top20 -cum
Showing nodes accounting for 104.70MB, 40.74% of 257.02MB total
Dropped 109 nodes (cum <= 1.29MB)
Showing top 20 nodes out of 125
      flat  flat%   sum%        cum   cum%
         0     0%     0%   100.85MB 39.24%  github.com/oklog/run.(*Group).Run.func1
         0     0%     0%   100.85MB 39.24%  github.com/parca-dev/parca-agent/pkg/profiler/cpu.(*CPU).Run
         0     0%     0%   100.85MB 39.24%  main.run.func6
         0     0%     0%   100.85MB 39.24%  main.run.func6.1
         0     0%     0%   100.85MB 39.24%  runtime/pprof.Do
         0     0%     0%    73.71MB 28.68%  github.com/godbus/dbus/v5.(*Conn).inWorker
    8.58MB  3.34%  3.34%    73.71MB 28.68%  github.com/godbus/dbus/v5.(*unixTransport).ReadMessage
    9.11MB  3.55%  6.88%    64.13MB 24.95%  github.com/godbus/dbus/v5.DecodeMessage
         0     0%  6.88%    55.02MB 21.41%  github.com/godbus/dbus/v5.(*decoder).Decode
      50MB 19.46% 26.34%    55.02MB 21.41%  github.com/godbus/dbus/v5.(*decoder).decode
    3.02MB  1.17% 27.51%    54.02MB 21.02%  github.com/coreos/go-systemd/v22/dbus.(*Conn).SubscribeUnitsCustom.func1
         0     0% 27.51%       51MB 19.84%  github.com/coreos/go-systemd/v22/dbus.(*Conn).ListUnits (inline)
         0     0% 27.51%       51MB 19.84%  github.com/coreos/go-systemd/v22/dbus.(*Conn).ListUnitsContext
   12.49MB  4.86% 32.37%       50MB 19.45%  github.com/coreos/go-systemd/v22/dbus.(*Conn).listUnitsInternal
         0     0% 32.37%    44.89MB 17.47%  github.com/parca-dev/parca-agent/pkg/metadata.(*StatelessProvider).Labels
         0     0% 32.37%    44.89MB 17.47%  github.com/parca-dev/parca-agent/pkg/metadata/labels.(*Manager).LabelSet
         0     0% 32.37%    44.89MB 17.47%  github.com/parca-dev/parca-agent/pkg/metadata/labels.(*Manager).labelSet
         0     0% 32.37%    44.39MB 17.27%  github.com/parca-dev/parca-agent/pkg/metadata.Compiler.func1
         0     0% 32.37%    42.50MB 16.54%  debug/elf.Open
   21.50MB  8.37% 40.74%    41.50MB 16.15%  debug/elf.NewFile

ROUTINE ======================== github.com/parca-dev/parca-agent/pkg/profiler.(*RemoteProfileWriter).Write in pkg/profiler/profile_writer.go
         0        2MB (flat, cum)  0.78% of Total
         .          .     73:	buf := bytes.NewBuffer(nil)
         .          .     74:	zw, err := gzip.NewWriterLevel(buf, gzip.StatelessCompression)
         .          .     75:	if err != nil {
         .          .     76:		return err
         .          .     77:	}
         .        1MB     78:	if err = prof.WriteUncompressed(zw); err != nil {
         .          .     79:		zw.Close()
         .          .     80:		return err
         .          .     81:	}
         .          .     82:	zw.Close()
         .          .     83:
         .          .     84:	_, err = rw.profileStoreClient.WriteRaw(ctx, &profilestorepb.WriteRawRequest{
         .          .     85:		Normalized: true,
         .          .     86:		Series: []*profilestorepb.RawProfileSeries{{
         .        1MB     87:			Labels: &profilestorepb.LabelSet{Labels: convertLabels(labels)},
         .          .     88:			Samples: []*profilestorepb.RawSample{{
         .          .     89:				RawProfile: buf.Bytes(),
         .          .     90:			}},
         .          .     91:		}},
         .          .     92:	})

The discussion is here #1056.

[kakkoyun]

LGTM

[brancz]

Just deployed this on the demo cluster, and I'm happy to report that this got us a healthy ~20% decrease in CPU usage, nice job, and thank you very much! 🎉

[brancz]

I'm especially impressed that this didn't need any pooling of byte buffers, just the replacement 🤯

[marselester]

Awesome! I am glad the change made a positive impact.