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From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
To: Finn Thain <fthain@linux-m68k.org>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Laurent Vivier" <laurent@vivier.eu>,
	qemu-devel@nongnu.org, "Greg Kurz" <groug@kaod.org>,
	qemu-ppc@nongnu.org, "David Gibson" <david@gibson.dropbear.id.au>
Subject: Re: [RFC 00/10] hw/mos6522: VIA timer emulation fixes and improvements
Date: Wed, 1 Sep 2021 09:06:06 +0100	[thread overview]
Message-ID: <f35346db-5246-73a7-d6dc-28492d922ed7@ilande.co.uk> (raw)
In-Reply-To: <abc8ceff-8336-b3b1-d5f1-37d412a393ca@ilande.co.uk>

On 01/09/2021 08:57, Mark Cave-Ayland wrote:

> I had a quick look at your via-timer branch at 
> https://github.com/fthain/qemu/commits/via-timer and spotted that your work is based 
> upon the v6.0 release. Before digging further into this, can you try using vanilla 
> git master or the v6.1 tag instead as there are a couple of related fixes from the 
> 6.1 development cycle that you are missing:
> 
> 82ff856fe7 ("mac_via: fix 60Hz VIA1 timer interval")
> - This fixed the 60Hz VIA1 timer interval (it was running 100x too fast) and so could 
> limit the virtual CPUs ability to process the 100Hz timer.
> 
> 30ca7eddc4 ("mac_via: remove VIA1 timer optimisations")
> - This fixed an issue whereby constant writes to portB would reset the 60Hz VIA1 
> timer and 1Hz VIA1 timer (Probably not relevant here, but worth having).

Ah my mistake, clearly not enough caffeine this morning - looks like these patches 
did make v6.0 after all :/

I'll have a go at some basic timer measurements using your patch to see what sort of 
numbers I get for the latency here. Obviously QEMU doesn't guarantee response times 
but over 20ms does seem high.


ATB,

Mark.


  reply	other threads:[~2021-09-01  8:07 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 10:09 [RFC 00/10] hw/mos6522: VIA timer emulation fixes and improvements Finn Thain
2021-08-24 10:09 ` [RFC 09/10] hw/mos6522: Avoid using discrepant QEMU clock values Finn Thain
2021-08-24 10:28   ` Philippe Mathieu-Daudé
2021-08-29  1:23     ` Finn Thain
2021-08-25  8:44   ` Mark Cave-Ayland
2021-08-29  1:55     ` Finn Thain
2021-08-24 10:09 ` [RFC 06/10] hw/mos6522: Implement oneshot mode Finn Thain
2021-08-25  8:18   ` Mark Cave-Ayland
2021-08-29  1:20     ` Finn Thain
2021-08-24 10:09 ` [RFC 01/10] hw/mos6522: Remove get_load_time() methods and functions Finn Thain
2021-08-24 10:29   ` Philippe Mathieu-Daudé
2021-08-25  6:55   ` Mark Cave-Ayland
2021-08-28  1:00     ` Finn Thain
2021-08-24 10:09 ` [RFC 08/10] hw/mos6522: Call mos6522_update_irq() when appropriate Finn Thain
2021-08-24 10:22   ` Philippe Mathieu-Daudé
2021-08-25  8:26   ` Mark Cave-Ayland
2021-08-24 10:09 ` [RFC 07/10] hw/mos6522: Fix initial timer counter reload Finn Thain
2021-08-25  8:23   ` Mark Cave-Ayland
2021-08-28  0:46     ` Finn Thain
2021-08-24 10:09 ` [RFC 10/10] hw/mos6522: Synchronize timer interrupt and timer counter Finn Thain
2021-08-25  8:52   ` Mark Cave-Ayland
2021-08-26  6:43     ` Finn Thain
2021-08-24 10:09 ` [RFC 04/10] hw/mos6522: Rename timer callback functions Finn Thain
2021-08-24 10:28   ` Philippe Mathieu-Daudé
2021-08-25  7:11   ` Mark Cave-Ayland
2021-08-26  7:42     ` Philippe Mathieu-Daudé
2021-08-24 10:09 ` [RFC 02/10] hw/mos6522: Remove get_counter_value() methods and functions Finn Thain
2021-08-24 10:29   ` Philippe Mathieu-Daudé
2021-08-24 10:09 ` [RFC 05/10] hw/mos6522: Don't clear T1 interrupt flag on latch write Finn Thain
2021-08-25  7:20   ` Mark Cave-Ayland
2021-08-26  5:21     ` Finn Thain
2021-09-01 14:32       ` Laurent Vivier
2021-09-01 22:26         ` Finn Thain
2021-08-24 10:09 ` [RFC 03/10] hw/mos6522: Remove redundant mos6522_timer1_update() calls Finn Thain
2021-08-25  7:09   ` Mark Cave-Ayland
2021-08-24 10:34 ` [RFC 00/10] hw/mos6522: VIA timer emulation fixes and improvements Philippe Mathieu-Daudé
2021-08-28  1:22   ` Finn Thain
2021-08-31 21:14     ` Mark Cave-Ayland
2021-08-31 22:44       ` Finn Thain
2021-09-01  7:57         ` Mark Cave-Ayland
2021-09-01  8:06           ` Mark Cave-Ayland [this message]
2021-09-10 17:29             ` Mark Cave-Ayland
2021-09-11  0:08               ` Finn Thain
2021-09-01  2:20       ` Finn Thain
2021-08-25  3:11 ` David Gibson
2021-08-25  9:10 ` Mark Cave-Ayland
2021-08-28  4:11   ` Finn Thain

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