Threads > 8 = multiple runs

[Moreno]

Hey guys,

Is there a reason why when I run tlp-stress with more than 8 threads, instead of running all the threads concurrently it will run multiple times?

Ex. If I run for 2 min and 2 threads it will run once for 2 min with 8 threads and then again for another 2 min with 2 threads.

If I run for 2 min and 16 threads it will run once for 2 min with 8 threads and then again for another 2 min with 8 threads (again).

See the attached file.

What am I missing?

[Anthony Grasso]

Hi Moreno,

Sorry for the late reply on this issue.

We have investigated the issue. In summary tlp-stress uses parallelStream() to create runner threads which is causing the problem. The function will create a thread pool that is limited to the number of cores in the machine. For example consider the case where you have 8 cores on the machine where tlp-stress is run. If you run a stress test with 16 threads, tlp-stress will run only 8 threads first, and then another 8 once the first batch is done.

We need to do one of the following:

• change the function we are using so that all threads can be launched at once, or 
• limit the number of threads that can run to the max number of cores.

Regards,

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[Moreno]

On Wednesday, September 9, 2020 at 12:36:43 AM UTC-3 anthony.grasso wrote:

Hi Moreno,

Sorry for the late reply on this issue.

We have investigated the issue. In summary tlp-stress uses parallelStream() to create runner threads which is causing the problem. The function will create a thread pool that is limited to the number of cores in the machine. For example consider the case where you have 8 cores on the machine where tlp-stress is run. If you run a stress test with 16 threads, tlp-stress will run only 8 threads first, and then another 8 once the first batch is done.

We need to do one of the following:

• change the function we are using so that all threads can be launched at once, or 

This is what most stress tools do.