From: Paolo Abeni <pabeni@redhat.com>
To: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Wei Wang <weiwan@google.com>, Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH net-next 1/2] net: updating dst lastusage is an unlikely event.
Date: Tue, 24 Oct 2017 12:39:45 +0200 [thread overview]
Message-ID: <1508841585.2758.10.camel@redhat.com> (raw)
In-Reply-To: <cb6e9e39bdcdaebba87e331d7b18392bdeefebc3.1508841315.git.pabeni@redhat.com>
On Tue, 2017-10-24 at 12:37 +0200, Paolo Abeni wrote:
> Since commit 0da4af00b2ed ("ipv6: only update __use and lastusetime
> once per jiffy at most"), updating the dst lastuse field is an
> unlikely action: it happens at most once per jiffy, out of
> potentially millions of calls per second.
>
> Mark explicitly the code as such, and let the compiler generate
> better code.
>
> Note: gcc 7.2 and several older versions do actually generate
> different - better - code when the unlikely() hint is in place,
> avoid jump in the fast path and keeping better code locality.
>
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Oops, I placed a bad subject prefix here, please ignore. I'll resend
soon with a proper one.
Sorry for the noise,
Paolo
prev parent reply other threads:[~2017-10-24 10:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-24 10:37 [PATCH net-next 1/2] net: updating dst lastusage is an unlikely event Paolo Abeni
2017-10-24 10:39 ` Paolo Abeni [this message]
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