FreeBSD 11.x thread creation time is 9000+ microseconds on Intel Xeon Gold series CPU

[Eugene Grosbein]

06.11.2018 20:43, Eugene Grosbein wrote:

>> I am seeing a FreeBSD 11.x OS poor performance issue .
>> CPU is Intel(R) Xeon(R) Gold 5115 CPU @ 2.40GHz ( dual socket CPU with 10
>> cores per socket )
>>
>> I have attached a simple program which creates thread and computes time
>> taken to create this thread. On this CPU with FreeBSD 11.x OS it takes 9000
>> to 15000 micro seconds ( us) to create
>> just one thread.
>>
>> On other platforms this thread creation time is usually 20 to 30 us only.
>> Any idea why it takes so much more time with FreeBSD 11.x ?
>> Is there any processor specific tuning that needs to be done ?
> 
> Please set "sysctl kern.eventtimer.periodic=1" and retry your tests.

Also "sysctl kern.timecounter.alloweddeviation=0" may help, too.