RE: OT: high WIO on Linux
- From: "Kevin Closson" <kevinc@xxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 10 Mar 2006 08:33:55 -0800
>>>
>>>First of all, Linux sucks. Let me clarify things a bit: the
>>>whole concept of %WIO makes me cringe. CPU works in user
>>>mode, kernel mode, is on the interrupt stack or is idle.
>>
I agree with Mladen on on this aspect of Linux (and many others).
The %WIO thing is goofy. I should point out, however, that the
interrupt handlers are kernel mode cycles. So it is actually,
Kernel,User, Idle loop. This is why a broken (chatty) hardware
device runs CPUs to saturation in kernel (sys) mode.
From a database perspective, Linux is about where good Unix
implementations where circa 1995. There were so many Oracle-special
OS features that the OSDs could exploit for scalability that
Linux can't dream of offering because the focus of Linux is
not RDBMS and the hardware is too general purpose--albeit EXTREMELY
fast in the case of AMD.
Like I say, Linux stands for (L)inux (I)s (N)ot (U)ni(X). But that
doesn't make it hopeless either. You just have to watch your
expectations.
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