Message-ID: <4ABBE9B7.1050505@gmail.com>
Date: Thu, 24 Sep 2009 23:50:47 +0200
From: Eric Dumazet <eric.dumazet@gmail.com>
User-Agent: Thunderbird 2.0.0.23 (Windows/20090812)
MIME-Version: 1.0
To: Ulrich Drepper <drepper@redhat.com>
CC: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= <fweisbec@gmail.com>,
       linux kernel <linux-kernel@vger.kernel.org>,
       linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] perf tools: Dont use openat()
References: <4ABB6EB7.7000002@gmail.com> <20090924131250.GA15132@elte.hu> <4ABB767D.6080004@gmail.com> <4ABBDF77.3090106@redhat.com>
In-Reply-To: <4ABBDF77.3090106@redhat.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1554
Lines: 41

Ulrich Drepper a écrit :
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Eric Dumazet wrote:
>>> We can certainly remove that reliance - wanna send a patch for it?
> 
> Come on, the silliness has to stop.  The kernel must be recent and to
> use it adequately the C library also must be recent.  And "recent" is
> not even correct anymore: the functions are available for more then two
> years.  Removing the use of the modern interfaces makes everything
> slower and might even re-introduce race conditions my patch fixed.
> 

First time I ear that C library *must* be recent. This was never
mentionned in Documentation/Changes, "Minimal Requirements"

"perf list" can be 100x slower, and even racy, I dont mind. At all.

$ time perf list >/dev/null 2>/dev/null

real    0m0.001s
user    0m0.000s
sys     0m0.001s

With openat(), I cannot use "perf" on machines I can only change kernel,
since changing glibc is too risky for legacy apps. I could use static and
private glibc, but last time I tried this I lost few hours and failed.

If modern interfaces means : "Upgrade glibc or die, silly you..."
I prefer to be silly, and keep increasing linux usability, even
if I dont have the chance to have a modern lab with up2date distros.

BTW, oprofile compiles perfectly on RHEL4 and 'old' glibc.

Thanks
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/