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From: "Aaron Gray" <angray AT beeb DOT net>
To: <cygwin AT cygwin DOT com>
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Subject: Re: Cygwin allocted time slice
Date: Thu, 14 Jun 2007 17:06:49 +0100
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> On Thu, Jun 14, 2007 at 04:20:04PM +0100, Aaron Gray wrote:
>>> On Thu, Jun 14, 2007 at 04:15:40AM +0100, Aaron Gray wrote:
>>>> Cygwin seems to only use a small amount of time slice relative to the
>>>> ammount of time slice availiable.  Compiles, builds and testsuite are
>>>> relly slow compared to MinGW which takes too much time.
>>>>
>>>> 'time' results confirm this.  Process time is about 1/4 of the total
>>>> system time.
>>>>
>>>> It i very noticable on compiling and testing GCC as compared to the
>>>> same on Linux or MinGW.
>>>>
>>>> Is there any way to give Cygwin a bigger slice of the pie ?
>>>>
>>>> Say 50% or 75% ?
>>>
>>> How do you suppose Cygwin is managing this interesting feat of only
>>> using some of the CPU time?  What Windows API is Cygwin using to just
>>> grab a small slice of the time?
>>
>> Weird I was getting very long compile times for GCC and on using 'time' 
>> was
>> getting indications that make was only getting 25% of total system time.
>>
>> I'll see if it is repeatable on another system.
>>
>>> As a follow-up question:  Why do you suppose we are punishing you by
>>> not allowing Cygwin to use all of the CPU by default?
>>>
>>> Oh.  Wait.  WJM.  Nevermind.
>>
>> Weird reply, no need to take the micky !
>
> You have apparently made an assumption that Cygwin is purposely using
> only a part of the CPU.  What's weird about asking for your rationale
> for why anyone would write a program which did such a thing, leaving it
> to some undocumented procedure to get better performance?  Why do you
> think we wouldn't just make this the default?
>
> In other words: your assumptions don't make a lot of sense.
>
> Here are some better assumptions:
>
> 1) Hey!  Maybe, since 'time' is a linux program, whatever is needed to get
> it to work accurately isn't well-implemented in Cygwin, so you can't trust
> its output.
>
> 2) Hey!  I just remembered that Cygwin is an emulation layer on top of
> Windows.  That means that there is a lot more code being executed than
> would be the case for MinGW!  Maybe *that's* why things are slower!

I'll take option 2, thank you :)

Aaron


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