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Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution
From: |
Alexander Graf |
Subject: |
Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution |
Date: |
Tue, 31 May 2011 17:44:13 +0200 |
On 31.05.2011, at 16:54, Jan Kiszka wrote:
> On 2011-05-31 16:26, Anthony Liguori wrote:
>> On 05/31/2011 09:06 AM, Jan Kiszka wrote:
>>> On 2011-05-31 15:47, Anthony Liguori wrote:
>>>> On 05/29/2011 04:50 PM, Andreas Färber wrote:
>>>>> BeOS and Haiku don't define SIGIO. When undefined, it won't arrive
>>>>> and doesn't need to be blocked.
>>>>>
>>>>> Signed-off-by: Andreas Färber<address@hidden>
>>>>
>>>> Anything to do with signal masks is never a trivial patch BTW...
>>>>
>>>> But I actually think explicit handling of SIGIO is unneeded. I think
>>>> this is a hold over from the pre-I/O thread days where we selectively
>>>> set SIGIO on certain file descriptors to make sure that when an IO fd
>>>> became readable, we received a signal to break out of the KVM emulation
>>>> loop.
>>>>
>>>> Can the folks on CC confirm/deny?
>>>>
>>>> I can't see any use of SIGIO in the current source tree.
>>>
>>> At least qemu-timer.c uses SIGIO in HPET mode. That only applies to
>>> Linux hosts, though.
>>
>> Is there any reason we still carry multiple timer implementations these
>> days?
>>
>> HPET shouldn't be any better than dynticks.
>
> On any recent kernel, for sure. BTW, the same applies to the RTC timer.
So the obvious change would be to introduce CONFIG_HPET, ifdef the SIGIO
handling on that and also ifdef the host hpet handling code on it? That way
it's documented well and can preferably even be turned off with
--disable-host-hpet during configure time, which we can then slowly turn to the
default.
Alex
- [Qemu-trivial] [PATCH] Use SIGIO with caution, Andreas Färber, 2011/05/29
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Anthony Liguori, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Jan Kiszka, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Anthony Liguori, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Jan Kiszka, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution,
Alexander Graf <=
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Anthony Liguori, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Alexander Graf, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Anthony Liguori, 2011/05/31
- Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Andreas Färber, 2011/05/31
- Re: [Qemu-trivial] [PATCH] Use SIGIO with caution, Jan Kiszka, 2011/05/31
- Re: [Qemu-trivial] [PATCH] Use SIGIO with caution, Anthony Liguori, 2011/05/31
Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Avi Kivity, 2011/05/31
Re: [Qemu-trivial] [Qemu-devel] [PATCH] Use SIGIO with caution, Andreas Färber, 2011/05/31