Τη Σάββατο, 29 Απριλίου 2017 - 7:33:00 π.μ. UTC+3, ο χρήστης Nikos Anastopoulos έγραψε: > > Either through the /proc/PID/tasks entries, or using > GODEBUG=schedtrace=1000.I get consistent results with both ways
With some experimentation more I did, I tend to believe this behavior has somehow to do with the number of CPUs of the platform; or to be more precise, to the number of CPUs made available to the Go app through the CPU affinity mask. When reducing the available CPUs from 88 to 44, 22, 11, and so on, the total number of threads after a 4-min run decreases as well, as you can see from the detailed results below (look at the "threads" field). So it is quite possible that if you try to reproduce the test on a low-count CPU environment you won't see anything weird. Here are my results on my 88-CPU platform: export GODEBUG=schedtrace=1000 1. [default, 88-cpus]: ./bench //after 4 min SCHED 240224ms: gomaxprocs=88 idleprocs=88 threads=29 spinningthreads=0 idlethreads=27 runqueue=0 [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] 2. [44-cpus]: $ taskset -ca 0-43 ./bench //after 4 min SCHED 240143ms: gomaxprocs=44 idleprocs=44 threads=26 spinningthreads=0 idlethreads=24 runqueue=0 [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] 3. [22-cpus]: $ taskset -ca 0-21 ./bench //after 4 min SCHED 240248ms: gomaxprocs=22 idleprocs=22 threads=23 spinningthreads=0 idlethreads=21 runqueue=0 [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] 4. [11-cpus]: $ taskset -ca 0-10 ./bench //after 4 min SCHED 240189ms: gomaxprocs=11 idleprocs=11 threads=12 spinningthreads=0 idlethreads=10 runqueue=0 [0 0 0 0 0 0 0 0 0 0 0] 239 81393 5. [8-cpus]: $ taskset -ca 0-7 ./bench //after 4 min SCHED 240201ms: gomaxprocs=8 idleprocs=8 threads=9 spinningthreads=0 idlethreads=7 runqueue=0 [0 0 0 0 0 0 0 0] 6. [4-cpus]: $ taskset -ca 0-3 ./bench //after 4 min SCHED 240184ms: gomaxprocs=4 idleprocs=4 threads=5 spinningthreads=0 idlethreads=3 runqueue=0 [0 0 0 0] 7. [2-cpus]: $ taskset -ca 0,1 ./bench //after 4 min SCHED 240171ms: gomaxprocs=2 idleprocs=2 threads=4 spinningthreads=0 idlethreads=2 runqueue=0 [0 0] 8. [1-cpu]: $ taskset -ca 0 ./bench //after 4 min SCHED 239437ms: gomaxprocs=1 idleprocs=1 threads=4 spinningthreads=0 idlethreads=2 runqueue=0 [0] I also checked if GOMAXPROCS is directly related, but I don't think so. For example, on a 2-CPU VM, I can perfectly set GOMAXPROCS=88 and run the app, but after the 4-min period the threads have reached a total count of 6: $ GOMAXPROCS=88 GODEBUG=schedtrace=1000 ./bench SCHED 240298ms: gomaxprocs=88 idleprocs=88 threads=6 spinningthreads=0 idlethreads=4 runqueue=0 [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] 239 81393 -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
