Re: regarding do_irq

[Sri Ram Vemulpali <sri.ram.gmu06@xxxxxxxxx>]

Hi,

Can any one explain, when interrupt handler schedules softirq, for bottom half work, when is that softirq is executed. Is it immediately after interrupt handler context or after some time later when scheduler was invoked. 

I am trying to understand execution context of BHs. I know that tasklets execute at relaxed time when system deems to execute. But what about softirq. Since softirq's are in nature high in priority, therefore they should run immediately after IRQ. I am trying to understand is there any latency between IRQ and softirq execution scheduled by that corresponding IRQ. Please can anyone explain the sequence of operations how the softirq is recognized (that it was set) and scheduled to execute.

Thanks,

Sri. 

On Thu, Sep 9, 2010 at 2:45 PM, Sri Ram Vemulpali <sri.ram.gmu06@xxxxxxxxx> wrote:

thanks to all

On Thu, Sep 9, 2010 at 8:16 AM, Bond <jamesbond.2k.g@xxxxxxxxx> wrote:

On Thu, Sep 9, 2010 at 1:10 PM, Dave Hylands <dhylands@xxxxxxxxx> wrote:

Well, check your CPU usage. It's probably less than 100%. Let's say
it's at 46%. That means that the system is spending 54% of its time
"doing nothing" or being idle.

>From a macroscopic level, it looks like the CPU is busy. But from a
microscopic level, the kernel is spending 540 millseconds out of every
second waiting for something to happen. Those 540 milliseconds are
when the kernel is idle.

--
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/

Thanks .