* Re: sleep and wakeup at microsecond boundary
[not found] <5.2.1.1.2.20040905085650.00b1e640@pop.gmx.net>
@ 2004-09-07 5:46 ` NucleoDyne Systems, Inc.
2004-09-07 6:13 ` Arjan van de Ven
0 siblings, 1 reply; 3+ messages in thread
From: NucleoDyne Systems, Inc. @ 2004-09-07 5:46 UTC (permalink / raw)
To: Mike Galbraith; +Cc: linux-kernel
Hello,
Let me explain the requirement a little more in detail.
Consider the routine sleep_on_timeout(, timeout) in sched.c:
A timer is started and then schedule() is called. The timer expires
after present jiffies + timeout (in jiffies) period.
On x86 the jiffies is updated every time PIT raises interrupt and
do_timer() is called, i.e. once in every 10ms.
So we can set timeout in multiples of 10ms.
We are developing a very powerful system (not x86 based) with multiple
CPUs, one of them will be running linux and will act as a co-processor
for the other CPUs running different OS.
On the CPU running linux we need to be able to call sleep_on_timeout()
with more granular expiration time, may be in multiples of microseconds.
I already have done the investigation and looking for feedback from the
developers on all possible issues.
Hope this explains.
Thanks,
Kallol Biswas
On Sun, 2004-09-05 at 00:09, Mike Galbraith wrote:
> At 12:51 PM 9/4/2004 -0700, NucleoDyne Systems, " "Inc. wrote:
> >Hello,
> > We have a requirement to implement the sleep and wakeup mechanism
> >at microsecond boundary in 2.4 kernel.
>
> I've re-visited this message about 10 times now, so I suppose I'm curious
> enough to ask: why on God's green Earth would someone want to do
> that? (to _any_ kernel, but I'm mostly wondering why [TILT] anyone would
> do such a thing to a GP kernel)
>
> -Mike
On Sat, 2004-09-04 at 12:51, NucleoDyne Systems, Inc. wrote: \
> Hello,
> We have a requirement to implement the sleep and wakeup mechanism
> at microsecond boundary in 2.4 kernel. The intent of this mail is to
> start a discussion on this topic and collect inputs from the kernel
> developers. Any reply on the issues of implementing such a feature will
> be greatly appreciated.
>
> Thanks,
> Kallol Biswas
--
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NucleoDyne Corporation
nucleon@nucleodyne.com
www.nucleodyne.com
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