[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emula
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift |
Date: |
Mon, 07 Feb 2011 15:43:08 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-02-07 15:28, Anthony Liguori wrote:
> On 02/07/2011 08:10 AM, Jan Kiszka wrote:
>> Again: please not in an ad-hoc fashion but as a generic services usable
>> by _all_ periodic timer sources that want to implement compensation.
>> This infrastructure should also be designed to once integrate IRQ
>> coalescing information as well.
>>
>> The point why I'm insisting on a broader solution is that both sources
>> for lost ticks (iothread and vcpu) end up in the same output: an
>> adjustment of the injection frequency of the affected timer device.
>> There is not "HPET" or "RTC" or "PIT" in this, all this may apply to the
>> SoC timer of some emulated ARM board as well.
>>
>
> Fair enough, how about:
>
> typedef struct PeriodicTimer PeriodicTimer;
>
> /**
> * @accumulated_ticks: the number of unacknowledged ticks in total
> since the creation of the timer
> **/
> typedef void (PeriodicTimer)(void *opaque, int accumulated_ticks);
I guess you mean PeriodicTimerFunc. Why the accumulated_ticks argument?
>
> PeriodicTimer *periodic_timer_new(PeriodicTimerFunc *cb, void *opaque);
>
> void periodic_timer_mod(PeriodicTimer *timer, int64_t interval, TimeUnit
> unit);
>
> /**
> * @policy: the drift catch-up policy
> * DRIFT_COMP_FAST, deliver next tick as soon as any
> tick is acknowledged if accumulated_ticks > 1
> * DRIFT_COMP_NONE, do not change interval regardless of
> accumulated ticks
> * DRIFT_COMP_GRADUAL, shorten interval by half until
> accumulated_ticks <= 1
> */
> void periodic_timer_set_policy(PeriodicTimer *timer,
> DriftCompensationPolicy policy);
>
> /**
> * @ticks: number of ticks to acknowledge that are currently outstanding.
> **/
> void periodic_timer_ack(PeriodicTimer *timer, int ticks);
>
Looks reasonable otherwise.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, (continued)
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Gleb Natapov, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Gleb Natapov, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Gleb Natapov, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Jan Kiszka, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift,
Jan Kiszka <=
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Jan Kiszka, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Jan Kiszka, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Jan Kiszka, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Anthony Liguori, 2011/02/07
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Avi Kivity, 2011/02/08
- Re: [Qemu-devel] Re: [RFC: 0/2] patch for QEMU HPET periodic timer emulation to alleviate time drift, Jan Kiszka, 2011/02/07