From: Johannes Berg <johannes@sipsolutions.net>
To: Janusz Dziedzic <janusz.dziedzic@tieto.com>,
linux-wireless@vger.kernel.org
Cc: nbd@openwrt.org
Subject: Re: [RFC/RFT 1/2] mac80211: Add NEED_ALIGNED4_SKBS hw flag
Date: Thu, 17 Dec 2015 11:29:43 +0100 [thread overview]
Message-ID: <1450348183.8247.24.camel@sipsolutions.net> (raw)
In-Reply-To: <1450344029-5296-1-git-send-email-janusz.dziedzic@tieto.com> (sfid-20151217_102050_152022_7DD1C619)
On Thu, 2015-12-17 at 10:20 +0100, Janusz Dziedzic wrote:
> HW/driver should set NEED_ALIGNED4_SKBS flag in case require
> aligned skbs to four-byte boundaries.
>
> Before we have to do memmove() in the driver before
> pass this to HW and memmove() back in tx completion.
> This patch allow to save CPU and skip such memmoves.
Can you quantify that btw? It shouldn't be that expensive since it's
all in the cache for read, so just has to be written out to RAM before
the DMA can happen... And on status it will be pulled into the cache
anyway, and you don't even need the write to happen before you can
continue.
johannes
next prev parent reply other threads:[~2015-12-17 10:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-17 9:20 [RFC/RFT 1/2] mac80211: Add NEED_ALIGNED4_SKBS hw flag Janusz Dziedzic
2015-12-17 9:20 ` [RFC/RFT 2/2] ath9k: request aligned skb Janusz Dziedzic
2015-12-21 18:53 ` Souptick Joarder
2015-12-21 22:48 ` Julian Calaby
2015-12-17 9:39 ` [RFC/RFT 1/2] mac80211: Add NEED_ALIGNED4_SKBS hw flag Felix Fietkau
2015-12-17 10:04 ` Johannes Berg
2015-12-17 10:09 ` Felix Fietkau
2015-12-17 10:12 ` Felix Fietkau
2015-12-18 8:43 ` Janusz Dziedzic
2015-12-17 10:29 ` Johannes Berg [this message]
2015-12-17 10:35 ` Felix Fietkau
2015-12-17 10:45 ` Johannes Berg
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