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From: David Miller <davem@davemloft.net>
To: shemminger@vyatta.com
Cc: kaber@trash.net, tgraf@suug.ch, Stephane_Chazelas@yahoo.fr,
	netdev@vger.kernel.org
Subject: Re: [PATCH] net: neighbour table ABI problem
Date: Wed, 21 May 2008 13:35:10 -0700 (PDT)	[thread overview]
Message-ID: <20080521.133510.145260976.davem@davemloft.net> (raw)
In-Reply-To: <20080521104019.22f9c712@extreme>

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 21 May 2008 10:40:19 -0700

> The neighbor table time of last use information is returned in the incorrect
> unit. Kernel to user space ABI's need to use USER_HZ (or milliseconds), otherwise
> the application has to try and discover the real system HZ value which is problematic.
> Linux has standardized on keeping USER_HZ consistent (100hz) even when kernel is
> running internally at some other value.
> 
> This change is small, but it breaks the ABI for older version of iproute2 utilities.
> But these utilities are already broken since they are looking at the psched_hz values
> which are completely different. So let's just go ahead and fix both kernel and user
> space. Older utilities will just print wrong values.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

In at least one sense the kernel has been providing a consistent
value :-)

I don't know what to do here, it's different from the other patch
you posted today in that I can't see any easy way to not change
behavior for old stuff.

Can we add a new attribute or something like that?

  reply	other threads:[~2008-05-21 20:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-21 16:38 [iproute2] get_hz() with CONFIG_HIGH_RES_TIMERS Stephane Chazelas
2008-05-21 16:56 ` Patrick McHardy
2008-05-21 17:40   ` [PATCH] net: neighbour table ABI problem Stephen Hemminger
2008-05-21 20:35     ` David Miller [this message]
2008-05-22  0:20       ` Thomas Graf
2008-06-03 23:03         ` David Miller
2008-05-21 17:10 ` [iproute2] get_hz() with CONFIG_HIGH_RES_TIMERS Stephen Hemminger
2008-05-21 18:43   ` route metrics in jiffies?? Stephen Hemminger
2008-05-21 20:31     ` David Miller
2008-05-22 10:36     ` rtt metric only for incoming connections? Stephane Chazelas
2008-05-27 18:43       ` Stephen Hemminger
2008-05-27 18:53         ` Rick Jones

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