[erlang-questions] Millions of processes?

Toby Thain <>
Thu Sep 25 16:30:01 CEST 2008


On 25-Sep-08, at 2:39 AM, Bengt Kleberg wrote:

> There where other micro kernels around at the time. At least 2 had
> benchmarks showing them to be faster than ''macro kernels''.

Does a generic 'faster' metric/scale really exist when comparing  
operating systems?

What I tend to see in benchmarks of complex systems like filesystems,  
databases, operating systems is that it's multivariate, workload  
dependent, and simply leads to differing sweet spots. And frequently,  
there are important attributes unconnected with performance...

--Toby

>
>
> bengt
>
> On Thu, 2008-09-25 at 15:20 +1000, jm wrote:
>> This was generally true only of the early micro kernels.  
>> Apparently, the
>> Mach kernel is slow when compared to the newer L4 kernel. see
>> http://en.wikipedia.org/wiki/L4_microkernel_family#History
>>
>> Jeff.
>>
>> Bengt Kleberg wrote:
>>> Greetings,
>>>
>>> It is not only _ideas_ in computer science that are held in  
>>> contempt (as
>>> quoted below). Ages ago (before 2000) I read an article about  
>>> Linux in
>>> embedded environments. The article quoted Linus Torvalds on why  
>>> not to
>>> use micro kernels. The reasons where that they are:
>>> 1 Experimental
>>> 2 Complex
>>> 3 Slow
>>>
>>> After looking around for a while I found plenty of articles about
>>> commercial micro kernels, and benchmarks showing micro kernels  
>>> running
>>> workloads faster than monolithic kernels. So 1 and 3 seemed to be
>>> incorrect.
>>> I submitted these findings to the magazine, which prompted an answer
>>> from Mr Torvalds. He assert that all three where true, but did not
>>> discuss what I had found. So (IMHO) it is also facts that are not  
>>> held
>>> in very high regard.
>>>
>>>
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