Re: [Qemu-devel] QEMU and Real Time OS

2015-02-02 Thread Marcelo Tosatti
On Fri, Jan 30, 2015 at 08:37:47AM +0100, Jan Kiszka wrote: On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why. I'd like to know if there is a certain reason why it doesn't work. Or if it should work and

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-30 Thread Marc Marí
El Fri, 30 Jan 2015 08:37:47 +0100 Jan Kiszka jan.kis...@siemens.com escribió: On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why. I'd like to know if there is a certain reason why it doesn't work. Or if

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-30 Thread Marc Marí
El Fri, 30 Jan 2015 11:36:37 +0100 Frederic Konrad fred.kon...@greensocs.com escribió: On 30/01/2015 11:26, Marc Marí wrote: El Fri, 30 Jan 2015 08:37:47 +0100 Jan Kiszka jan.kis...@siemens.com escribió: On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote:

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-30 Thread Frederic Konrad
On 30/01/2015 11:26, Marc Marí wrote: El Fri, 30 Jan 2015 08:37:47 +0100 Jan Kiszka jan.kis...@siemens.com escribió: On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why. I'd like to know if there is a certain reason

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-30 Thread Jan Kiszka
On 2015-01-30 11:36, Frederic Konrad wrote: On 30/01/2015 11:26, Marc Marí wrote: El Fri, 30 Jan 2015 08:37:47 +0100 Jan Kiszka jan.kis...@siemens.com escribió: On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why.

[Qemu-devel] QEMU and Real Time OS

2015-01-29 Thread Marc Marí
Hi I tried to run a Linux Kernel with Preempt RT patch on a QEMU emulated machine using TCG (ARM guest, x86_64 guest). I expected the guest to have high latencies, but more or less constant. But I found, using cyclictest, a lot of randomness and a lot of difference between the average and the

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-29 Thread Paolo Bonzini
On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why. I'd like to know if there is a certain reason why it doesn't work. Or if it should work and the problem is too much I/O overhead. Or any other hint to understand it. It is due to latencies in the host.

Re: [Qemu-devel] QEMU and Real Time OS

2015-01-29 Thread Jan Kiszka
On 2015-01-30 00:06, Paolo Bonzini wrote: On 29/01/2015 20:37, Marc Marí wrote: Is this an expected behaviour? I can't see why. I'd like to know if there is a certain reason why it doesn't work. Or if it should work and the problem is too much I/O overhead. Or any other hint to