From: Al Viro <viro@ZenIV.linux.org.uk>
To: David Miller <davem@davemloft.net>
Cc: f.fainelli@gmail.com, netdev@vger.kernel.org, opendmb@gmail.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 1/2] net: bcmgenet: Fix sparse warnings in bcmgenet_put_tx_csum()
Date: Tue, 3 Apr 2018 17:45:45 +0100 [thread overview]
Message-ID: <20180403164545.GK30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180403.123305.1783530733365447500.davem@davemloft.net>
On Tue, Apr 03, 2018 at 12:33:05PM -0400, David Miller wrote:
> Yes Al, however the pattern choosen here is probably cheaper on little endian:
>
> __beXX val = x;
> switch (val) {
> case htons(ETH_P_FOO):
> ...
> }
>
> This way only the compiler byte swaps the constants at compile time,
> no code is actually generated to do it.
That's not obvious, actually - depends upon how sparse the switch ends
up being. You can easily lose more than a single byteswap insn on
worse cascase of comparisons.
next prev parent reply other threads:[~2018-04-03 16:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-02 22:58 [PATCH net 0/2] net: Broadcom drivers sparse fixes Florian Fainelli
2018-04-02 22:58 ` [PATCH net 1/2] net: bcmgenet: Fix sparse warnings in bcmgenet_put_tx_csum() Florian Fainelli
2018-04-03 16:29 ` Al Viro
2018-04-03 16:33 ` David Miller
2018-04-03 16:45 ` Al Viro [this message]
2018-04-03 20:40 ` Florian Fainelli
2018-04-02 22:58 ` [PATCH net 2/2] net: systemport: Fix sparse warnings in bcm_sysport_insert_tsb() Florian Fainelli
2018-04-03 16:23 ` Al Viro
2018-04-04 15:07 ` [PATCH net 0/2] net: Broadcom drivers sparse fixes David Miller
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