[RFT][patch] Scheduling for HTT and not only

Alexander Motin mav at FreeBSD.org
Tue Apr 10 17:18:51 UTC 2012


On 04/10/12 19:58, Arnaud Lacombe wrote:
> 2012/4/9 Alexander Motin<mav at freebsd.org>:
>> [...]
>>
>> I have strong feeling that while this test may be interesting for profiling,
>> it's own results in first place depend not from how fast scheduler is, but
>> from the pipes capacity and other alike things. Can somebody hint me what
>> except pipe capacity and context switch to unblocked receiver prevents
>> sender from sending all data in batch and then receiver from receiving them
>> all in batch? If different OSes have different policies there, I think
>> results could be incomparable.
>>
> Let me disagree on your conclusion. If OS A does a task in X seconds,
> and OS B does the same task in Y seconds, if Y>  X, then OS B is just
> not performing good enough. Internal implementation's difference for
> the task can not be waived as an excuse for result's comparability.

Sure, numbers are always numbers, but the question is what are they 
showing? Understanding of the test results is even more important for 
purely synthetic tests like this. Especially when one test run gives 25 
seconds, while another gives 50. This test is not completely clear to me 
and that is what I've told.

-- 
Alexander Motin


More information about the freebsd-current mailing list