high cpu usage with abaco source

[ggggggggg]

I'm running in bluefors with a reported 2x64 (actually should be 2x32 I think) abaco source with a reported data rate of 32.3MB/s and 4.096 us/sample. I'm running edge multi triggers and off files and top reports 250-300% cpu usage for dastard.

This compares to about 200% cpu usage for a tdm system of 8x32 at 200 MB/s, which should be doing more work than the above config. Likely culprits include parsing all the packet headers and biased unwrapping.

[joefowler]

I am seeing the same problem, but thanks for the specifics. This will be an important priority in the very near future.

[joefowler]

We'll plan to do a comparison head to head between µMUX with Abaco+UDP vs a TDM system at comparable data rates. (If a TDM has 200 MB/sec, but only half that is from feedback channels, is a "comparable" µMUX system running at 100 or 200 MB/sec?)

Things to investigate:

1. How does the load reported by top change when you change the # of channels? How about the profile reported in the go profiling tool?
2. I think that the AbacoSource.readerMainLoop() shows that we're doing quite a few activities in a single goroutine. The most important might be the group.demuxData(...) call, which we've seen to cause some 10-20% of all CPU time (according to the profiler, at least). If necessary, maybe we can think up a way to parallelize the demux step, sharing among maybe one goroutine per channel group?
3. EMT triggering algorithms can probably be made more compute-efficient. (But we're not there yet!)