Re: serial problems cont..

[Michael Malone <michael.malone@tait.co.nz>]

Avi Kivity wrote:
> Michael Malone wrote:
>> Hi everyone,
>>
>> I've written a couple of questions regarding the serial device in 
>> KVM.  After slightly more investigation I think I have found what's 
>> going awry.  Correct me if I'm wrong, but I believe that KVM 
>> generates an interrupt for every single character it sends through 
>> the serial port.  This throws CPU usage through the roof and I 
>> suspect this means that the timers aren't being handled correctly and 
>> it failed on a string of 0's for me due to the timing slips.  
>> GNU/Linux and Windows don't have anywhere near the processor usage 
>> for their serial ports.  Now, I know nothing of serial programming 
>> and don't have any time to investigate it too heavily just now, but I 
>> have pulled down the source and had a look through that, but it looks 
>> to be doing the right thing (I suppose?).   I was mainly wondering 
>> how GNU/Linux and windows handle serial interrupts or if some of the 
>> serial character events could be buffered, rather than overload the 
>> processor?  I guess this is a low priority for you, but any help 
>> would be greatly appreciated (And when I have some more time, I will 
>> spend some of it helping to develop KVM! Quid pro quo, Clarice...)
>>
>
> What version of kvm are you testing?  There were some changes to the 
> serial emulation recently.  See for example 
> 02f0b4c0cc26f3a2578d515d96781f5a6258888d in kvm-73.
>
I have tried with kvm 62, 69, 72 and 74.  All of them gave the same 
result.  What do you mean by "See for example 
02f0b4c0cc26f3a2578d515d96781f5a6258888d"?
- I am running Ubuntu 8.04 (Hardy) as host and Windows XP as guest on an 
Intel Core 2 duo processor.

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