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gccgo: alloc space keeps on increasing even with a simple go program using grpc #25103

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amandeepgautam opened this issue Apr 26, 2018 · 2 comments
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gccgo: alloc space keeps on increasing even with a simple go program using grpc #25103

amandeepgautam opened this issue Apr 26, 2018 · 2 comments
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FrozenDueToAge NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. WaitingForInfo Issue is not actionable because of missing required information, which needs to be provided.
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Gccgo

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@amandeepgautam
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amandeepgautam commented Apr 26, 2018 •
edited

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.10 gccgo (GCC) 8.0.1 20180305 (experimental) aix/ppc

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

OS: AIX 7.2
relevant go env flags:
GOARCH="ppc"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build337480888=/tmp/go-build -gno-record-gcc-switches -funwind-tables"

What did you do?

I have a simple grpc server and a client with makes request frequently. The program can be found here. Please create a dir and extract the contents of the tar file to it. Make sure that $GOPATH is exported correctly. Execute ./run.sh.

What did you expect to see?

The DATA RES section should be stable in terms of memory usage

What did you see instead?

For a program running days, this memory bloats up to 5-6 GB and then the system freezes. Surprisingly the program does not crash. For this particular example, following is the pprof output at the start of the program and hew seconds later:

At the start of the program:

 go tool pprof --alloc_space http://10.2.144.87:50048/debug/pprof/heap
Fetching profile from http://10.2.144.87:50048/debug/pprof/heap
Saved profile in /home/cohesity/pprof/pprof.10.2.144.87:50048.alloc_objects.alloc_space.inuse_objects.inuse_space.013.pb.gz
Entering interactive mode (type "help" for commands)
(pprof) top
15364.38kB of 18436.46kB total (83.34%)
Showing top 10 nodes out of 30 (cum >= 512.03kB)
      flat  flat%   sum%        cum   cum%
 3584.45kB 19.44% 19.44% 13316.25kB 72.23%  google_golang_org_grpc.Server.serveStreams
 3072.35kB 16.66% 36.11%  3072.35kB 16.66%  golang_org_x_net_http2_hpack.Decoder.parseFieldIndexed
 1536.52kB  8.33% 44.44%  1536.52kB  8.33%  google_golang_org_grpc_transport.decodeState.processHeaderField
 1536.14kB  8.33% 52.77%  4608.77kB 25.00%  google_golang_org_grpc_transport.http2Server.operateHeaders
 1536.12kB  8.33% 61.10%  1536.12kB  8.33%  golang_org_x_net_context.WithDeadline
 1536.05kB  8.33% 69.44%  9731.80kB 52.79%  google_golang_org_grpc_transport.http2Server.HandleStreams
 1024.06kB  5.55% 74.99%  1024.06kB  5.55%  google_golang_org_grpc_transport.loopyWriter.run
  514.63kB  2.79% 77.78%   514.63kB  2.79%  golang_org_x_net_http2_hpack.Decoder.parseFieldLiteral
  512.04kB  2.78% 80.56%  1024.05kB  5.55%  google_golang_org_grpc.Server.sendResponse
  512.03kB  2.78% 83.34%   512.03kB  2.78%  golang_org_x_net_trace.FromContext

A few minutes later:

 go tool pprof --alloc_space http://10.2.144.87:50048/debug/pprof/heap
Fetching profile from http://10.2.144.87:50048/debug/pprof/heap
Saved profile in /home/cohesity/pprof/pprof.10.2.144.87:50048.alloc_objects.alloc_space.inuse_objects.inuse_space.014.pb.gz
Entering interactive mode (type "help" for commands)
(pprof) top
125.01MB of 171.64MB total (72.84%)
Dropped 7 nodes (cum <= 0.86MB)
Showing top 10 nodes out of 58 (cum >= 4.50MB)
      flat  flat%   sum%        cum   cum%
   23.50MB 13.69% 13.69%    86.52MB 50.41%  google_golang_org_grpc_transport.http2Server.HandleStreams
      23MB 13.40% 27.09%   109.52MB 63.81%  google_golang_org_grpc.Server.serveStreams
      17MB  9.91% 37.00%       17MB  9.91%  golang_org_x_net_http2_hpack.Decoder.parseFieldIndexed
   12.50MB  7.28% 44.29%       13MB  7.58%  google_golang_org_grpc_transport.decodeState.processHeaderField
   10.50MB  6.12% 50.40%       55MB 32.05%  google_golang_org_grpc..1google_golang_org_grpc.Server.serveStreams..func2
       9MB  5.24% 55.65%        9MB  5.24%  google_golang_org_grpc_transport.controlBuffer.put
    8.50MB  4.95% 60.60%       13MB  7.57%  golang_org_x_net_context.WithTimeout
    8.50MB  4.95% 65.55%       40MB 23.31%  google_golang_org_grpc.Server.handleStream
       8MB  4.66% 70.21%    31.50MB 18.35%  google_golang_org_grpc.Server.processUnaryRPC
    4.50MB  2.62% 72.84%     4.50MB  2.62%  golang_org_x_net_trace.FromContext
@gopherbot gopherbot added this to the Gccgo milestone Apr 26, 2018
@agnivade agnivade added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Apr 26, 2018
@bcmills
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bcmills commented Apr 26, 2018

In server.go, you have

  // This call enables profiling of goroutine blocks for pprof.
  // https://software.intel.com/en-us/blogs/2014/05/10/debugging-performance-issues-in-go-programs
  runtime.SetBlockProfileRate(1)

Do you still observe the memory growth if you remove that?

@bcmills bcmills added the WaitingForInfo Issue is not actionable because of missing required information, which needs to be provided. label Apr 26, 2018
@gopherbot
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Timed out in state WaitingForInfo. Closing.

(I am just a bot, though. Please speak up if this is a mistake or you have the requested information.)

@golang golang locked and limited conversation to collaborators May 26, 2019
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