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From: Johannes Berg <johannes@sipsolutions.net>
To: Marco Porsch <marco@cozybit.com>
Cc: mcgrof@qca.qualcomm.com, jouni@qca.qualcomm.com,
	vthiagar@qca.qualcomm.com, senthilb@qca.qualcomm.com,
	linux-wireless@vger.kernel.org, devel@lists.open80211s.org,
	ath9k-devel@lists.ath9k.org
Subject: Re: [PATCH 1/3] mac80211: move mesh sync beacon handler into neighbour_update
Date: Fri, 15 Feb 2013 14:58:28 +0100	[thread overview]
Message-ID: <1360936708.15040.18.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <511E3CB7.4040207@cozybit.com> (sfid-20130215_144844_328347_5B0B2D91)

On Fri, 2013-02-15 at 14:48 +0100, Marco Porsch wrote:

> > I'm talking about this API:
> >
> > mesh_neighbour_update:
> > ...
> > 	tsf = drv_get_tsf()
> > ...
> > 	sync_ops->rx_bcn(..., tsf)
> >
> >
> > mesh_sync_offset_rx_bcn(..., t_r):
> > 	...
> > 	if (have_better_timestamp)
> > 		t_r = get_better_timestamp()
> >
> >
> > You can hardly claim that's an intuitive API.
> 
> Hm, alright. Just saying that ieee80211_mps_sta_tbtt_update still uses 
> the unchanged TSF value. But hey :)

Well, that function doesn't exist in this patch...

> What would be more favourable then?

I guess you can tell I'm not in a good mood today. I think any use of
get_tsf() for operation is a complete waste of time, there's no way you
can get the timings correct. You could be preempted, and suddenly sleep
for a few tens or hundreds milliseconds, so none of this makes any
sense... To properly do it you have to do calculations in relative times
and let the device apply them.

johannes


WARNING: multiple messages have this Message-ID (diff)
From: Johannes Berg <johannes@sipsolutions.net>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] [PATCH 1/3] mac80211: move mesh sync beacon handler into neighbour_update
Date: Fri, 15 Feb 2013 14:58:28 +0100	[thread overview]
Message-ID: <1360936708.15040.18.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <511E3CB7.4040207@cozybit.com> (sfid-20130215_144844_328347_5B0B2D91)

On Fri, 2013-02-15 at 14:48 +0100, Marco Porsch wrote:

> > I'm talking about this API:
> >
> > mesh_neighbour_update:
> > ...
> > 	tsf = drv_get_tsf()
> > ...
> > 	sync_ops->rx_bcn(..., tsf)
> >
> >
> > mesh_sync_offset_rx_bcn(..., t_r):
> > 	...
> > 	if (have_better_timestamp)
> > 		t_r = get_better_timestamp()
> >
> >
> > You can hardly claim that's an intuitive API.
> 
> Hm, alright. Just saying that ieee80211_mps_sta_tbtt_update still uses 
> the unchanged TSF value. But hey :)

Well, that function doesn't exist in this patch...

> What would be more favourable then?

I guess you can tell I'm not in a good mood today. I think any use of
get_tsf() for operation is a complete waste of time, there's no way you
can get the timings correct. You could be preempted, and suddenly sleep
for a few tens or hundreds milliseconds, so none of this makes any
sense... To properly do it you have to do calculations in relative times
and let the device apply them.

johannes

  reply	other threads:[~2013-02-15 13:58 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-15 11:40 [PATCH 1/3] mac80211: move mesh sync beacon handler into neighbour_update Marco Porsch
2013-02-15 11:40 ` [ath9k-devel] " Marco Porsch
2013-02-15 11:40 ` [PATCH 2/3] mac80211: mesh power save doze scheduling Marco Porsch
2013-02-15 11:40   ` [ath9k-devel] " Marco Porsch
2013-02-15 11:40 ` [PATCH 3/3] ath9k: mesh powersave support Marco Porsch
2013-02-15 11:40   ` [ath9k-devel] " Marco Porsch
2013-02-15 12:14 ` [PATCH 1/3] mac80211: move mesh sync beacon handler into neighbour_update Johannes Berg
2013-02-15 12:14   ` [ath9k-devel] " Johannes Berg
2013-02-15 12:40   ` Bob Copeland
2013-02-15 12:40     ` [ath9k-devel] " Bob Copeland
2013-02-15 12:42     ` Bob Copeland
2013-02-15 12:42       ` [ath9k-devel] " Bob Copeland
2013-02-15 13:30       ` Marco Porsch
2013-02-15 13:30         ` [ath9k-devel] " Marco Porsch
2013-02-15 12:40   ` marco
2013-02-15 12:40     ` [ath9k-devel] " marco at cozybit.com
2013-02-15 12:46     ` Johannes Berg
2013-02-15 12:46       ` [ath9k-devel] " Johannes Berg
2013-02-15 13:31       ` Marco Porsch
2013-02-15 13:31         ` [ath9k-devel] " Marco Porsch
2013-02-15 13:37         ` Johannes Berg
2013-02-15 13:37           ` [ath9k-devel] " Johannes Berg
2013-02-15 13:48           ` Marco Porsch
2013-02-15 13:48             ` [ath9k-devel] " Marco Porsch
2013-02-15 13:58             ` Johannes Berg [this message]
2013-02-15 13:58               ` Johannes Berg
2013-02-18 15:07               ` Marco Porsch
2013-02-18 15:07                 ` [ath9k-devel] " Marco Porsch
2013-02-18 15:20                 ` Johannes Berg
2013-02-18 15:20                   ` [ath9k-devel] " Johannes Berg

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