Go Execution Trace Size Breakdown

I'm currently trying to get a better understanding of the data produced by Go's execution tracer (aka runtime/trace). One thing I'm interested in is the breakdown of trace sizes.

For this purpose I've just added a new breakdown command (docs) to my traceutils project. I haven't had a chance to analyze a lot of different traces yet, but it was already very interesting to see the results for a big 280MiB trace that I had laying around.

I didn't know what to expect, but seeing almost 22% of the trace being made up of EventGoSysCall events was definitely surprising. Perhaps its indicative of poorly buffered I/O operations?

Another trace I looked at spends only 1% of its size on this event type. It will be interesting to see what patterns emerge when looking at more data.

$ traceutils breakdown bytes big.trace
+------------------------+----------+---------+
|       EVENT TYPE       |  BYTES   |    %    |
+------------------------+----------+---------+
| EventGoSysCall         | 63.1 MB  | 21.84%  |
| EventGoCreate          | 60.2 MB  | 20.86%  |
| EventGoStartLocal      | 44.6 MB  | 15.44%  |
| EventGoUnblock         | 38.5 MB  | 13.34%  |
| EventGoStart           | 19.8 MB  | 6.85%   |
| EventGoBlockRecv       | 14.7 MB  | 5.09%   |
| EventHeapAlloc         | 14.1 MB  | 4.90%   |
| EventGoEnd             | 11.1 MB  | 3.83%   |
| EventGoSched           | 8.7 MB   | 3.00%   |
| EventGoUnblockLocal    | 4.8 MB   | 1.67%   |
| EventGoBlockSync       | 4.7 MB   | 1.63%   |
| EventGoSysExit         | 1.1 MB   | 0.37%   |
| EventStack             | 783.3 kB | 0.27%   |
| EventCPUSample         | 497.4 kB | 0.17%   |
| EventProcStart         | 445.9 kB | 0.15%   |
| EventGoBlockSend       | 291.5 kB | 0.10%   |
| EventGoSysBlock        | 284.1 kB | 0.10%   |
| EventGCSweepDone       | 275.7 kB | 0.10%   |
| EventProcStop          | 218.9 kB | 0.08%   |
| EventGCSweepStart      | 202.3 kB | 0.07%   |
| EventGoBlockSelect     | 184.8 kB | 0.06%   |
| EventString            | 72.5 kB  | 0.03%   |
| EventBatch             | 36.2 kB  | 0.01%   |
| EventGoPreempt         | 34.4 kB  | 0.01%   |
| EventGoBlock           | 28.1 kB  | 0.01%   |
| EventGCMarkAssistStart | 27.3 kB  | 0.01%   |
| EventGCMarkAssistDone  | 21.5 kB  | 0.01%   |
| EventGoStartLabel      | 14.8 kB  | 0.01%   |
| EventGoWaiting         | 9.4 kB   | 0.00%   |
| EventGoBlockNet        | 2.1 kB   | 0.00%   |
| EventGoSleep           | 364 B    | 0.00%   |
| EventGomaxprocs        | 49 B     | 0.00%   |
| EventGCSTWStart        | 39 B     | 0.00%   |
| EventHeapGoal          | 28 B     | 0.00%   |
| EventGCSTWDone         | 24 B     | 0.00%   |
| EventGCStart           | 20 B     | 0.00%   |
| EventGoInSyscall       | 16 B     | 0.00%   |
| EventGCDone            | 8 B      | 0.00%   |
| EventGoBlockCond       | 5 B      | 0.00%   |
| EventFrequency         | 5 B      | 0.00%   |
+------------------------+----------+---------+
|         TOTAL          | 288.7 MB | 100.00% |
+------------------------+----------+---------+