I've been working on optimizing code that analyzes social graph data (with lots of help from https://blog.golang.org/profiling-go-programs) and I've successfully reworked a lot of slow code.
All data is loaded into memory from db first, and the data analysis from there appears CPU bound (max memory consumption < 10MB, CPU1 @ 100%)
But now most of my program's time seems to be in runtime.osyield and runtime.usleep. What's the way to prevent that?
I've set GOMAXPROCS=1 and the code does not spawn any goroutines (other than what the golang libraries may call).
This is my top10 output from pprof
(pprof) top10
62550ms of 72360ms total (86.44%)
Dropped 208 nodes (cum <= 361.80ms)
Showing top 10 nodes out of 77 (cum >= 1040ms)
flat flat% sum% cum cum%
20760ms 28.69% 28.69% 20850ms 28.81% runtime.osyield
14070ms 19.44% 48.13% 14080ms 19.46% runtime.usleep
11740ms 16.22% 64.36% 23100ms 31.92% _/C_/code/sc_proto/cloudgraph.(*Graph).LeafProb
6170ms 8.53% 72.89% 6170ms 8.53% runtime.memmove
4740ms 6.55% 79.44% 10660ms 14.73% runtime.typedslicecopy
2040ms 2.82% 82.26% 2040ms 2.82% _/C_/code/sc_proto.mAvg
890ms 1.23% 83.49% 1590ms 2.20% runtime.scanobject
770ms 1.06% 84.55% 1420ms 1.96% runtime.mallocgc
760ms 1.05% 85.60% 760ms 1.05% runtime.heapBitsForObject
610ms 0.84% 86.44% 1040ms 1.44% _/C_/code/sc_proto/cloudgraph.(*Node).DeepestChildren
(pprof)
The _ /C_/code/sc_proto/* functions are my code.
(better, SVG version of graph here: https://goo.gl/Tyc6X4)