From: David Miller <davem@davemloft.net>
To: daniel.marjamaki@gmail.com
Cc: netdev@vger.kernel.org, kernel-janitors@lists.osdl.org,
linux-kernel@vger.kernel.org
Subject: Re: [KJ] [PATCH] net/core/flow.c: compare data with memcmp
Date: Mon, 01 Jan 2007 08:49:05 +0000 [thread overview]
Message-ID: <20070101.004905.98552337.davem@davemloft.net> (raw)
In-Reply-To: <80ec54e90612312347w2b906e5eg725a7761110c6897@mail.gmail.com>
From: "Daniel_Marjamäki" <daniel.marjamaki@gmail.com>
Date: Mon, 1 Jan 2007 08:47:48 +0100
> So you mean that in this particular case it's faster with a handcoded
> comparison than memcmp? Because both key1 and key2 are located at
> word-aligned addresses?
> That's fascinating.
Essentially, yes.
However, I wonder. GCC should be able to see this also, and
if it expands the memset() inline the code emitted should be
very similar.
It is something to investigate on a few cpu types, for sure.
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WARNING: multiple messages have this Message-ID (diff)
From: David Miller <davem@davemloft.net>
To: daniel.marjamaki@gmail.com
Cc: netdev@vger.kernel.org, kernel-janitors@lists.osdl.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net/core/flow.c: compare data with memcmp
Date: Mon, 01 Jan 2007 00:49:05 -0800 (PST) [thread overview]
Message-ID: <20070101.004905.98552337.davem@davemloft.net> (raw)
In-Reply-To: <80ec54e90612312347w2b906e5eg725a7761110c6897@mail.gmail.com>
From: "Daniel_Marjamäki" <daniel.marjamaki@gmail.com>
Date: Mon, 1 Jan 2007 08:47:48 +0100
> So you mean that in this particular case it's faster with a handcoded
> comparison than memcmp? Because both key1 and key2 are located at
> word-aligned addresses?
> That's fascinating.
Essentially, yes.
However, I wonder. GCC should be able to see this also, and
if it expands the memset() inline the code emitted should be
very similar.
It is something to investigate on a few cpu types, for sure.
next prev parent reply other threads:[~2007-01-01 8:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-31 16:37 [KJ] [PATCH] net/core/flow.c: compare data with memcmp Daniel Marjamäki
2006-12-31 16:37 ` Daniel Marjamäki
2006-12-31 19:49 ` [KJ] " Nishanth Aravamudan
2006-12-31 19:49 ` Nishanth Aravamudan
2006-12-31 20:37 ` David Miller
2006-12-31 20:37 ` David Miller
2007-01-01 7:47 ` [KJ] " Daniel Marjamäki
2007-01-01 7:47 ` Daniel Marjamäki
2007-01-01 8:49 ` David Miller [this message]
2007-01-01 8:49 ` David Miller
2007-01-01 9:16 ` [KJ] " Daniel Marjamäki
2007-01-01 9:16 ` Daniel Marjamäki
2007-01-02 23:36 ` [KJ] " David Miller
2007-01-02 23:36 ` David Miller
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