Experience using virtual threads in EA 23-loom+4-102

[Alan Bateman]

On 24/06/2024 18:24, Matthew Swift wrote:
> :
>
>
>
> I reran the test and executed the above command once per second for 10 
> seconds:
>
> $ for i in 1 2 3 4 5 6 7 8 9 10; do jcmd DirectoryServer 
> Thread.vthread_scheduler; sleep 1; done
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 13, running = 0, steals = 17676052, tasks = 0, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 16, running = 0, steals = 17784106, tasks = 1, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 20, running = 1, steals = 17887000, tasks = 1, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 15, running = 1, steals = 17984238, tasks = 1, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 9, running = 0, steals = 18082247, tasks = 0, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 9, running = 0, steals = 18201916, tasks = 0, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 20, running = 0, steals = 18302449, tasks = 2, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 1, running = 0, steals = 18416910, tasks = 0, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 13, running = 0, steals = 18516576, tasks = 0, 
> submissions = 0]
> 110886:
> java.util.concurrent.ForkJoinPool at 3a7204cd[Running, parallelism = 20, 
> size = 20, active = 14, running = 0, steals = 18602916, tasks = 0, 
> submissions = 0]
>
> I won't pretend to understand what this means :-)
>
Thanks, I mostly wanted to see the values for the "tasks" and 
"submissions" in the output. These are the number of virtual threads 
that are waiting to execute in both local queues and unowned submission 
queues. There are 0, except for the sample where all 20 workers are 
active and 2 virtual threads have been unparked and are waiting to 
continue. So that doesn't explain the outliers you see.

-Alan
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