Date: Fri, 25 Mar 2005 14:45:19 -0800 (PST)
From: dean gaudet <dean-list-linux-kernel@arctic.org>
To: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
cc: Andrew Morton <akpm@osdl.org>, Greg KH <greg@kroah.com>,
       lkml <linux-kernel@vger.kernel.org>,
       Evgeniy Polyakov <johnpol@2ka.mipt.ru>, Jay Lan <jlan@engr.sgi.com>,
       Erich Focht <efocht@hpce.nec.com>, Ram <linuxram@us.ibm.com>,
       Gerrit Huizenga <gh@us.ibm.com>,
       elsa-devel <elsa-devel@lists.sourceforge.net>
Subject: Re: [patch 1/2] fork_connector: add a fork connector
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Message-ID: <Pine.LNX.4.62.0503251440260.1481@twinlark.arctic.org>
References: <1111745010.684.49.camel@frecb000711.frec.bull.fr>
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On Fri, 25 Mar 2005, Guillaume Thouvenin wrote:

...
>   The lmbench shows that the overhead (the construction and the sending
> of the message) in the fork() routine is around 7%.
...
> +		/* 
> +		 * size of data is the number of characters 
> +		 * printed plus one for the trailing '\0'
> +		 */
> +		memset(msg->data, '\0', CN_FORK_INFO_SIZE);
> +		msg->len = scnprintf(msg->data, CN_FORK_INFO_SIZE-1, 
> +				    "%i %i %i", 
> +				    smp_processor_id(), parent, child) + 1;

i'm certain that if you used a struct {} and filled in 3 fields rather 
than zeroing 64 bytes of memory, and doing 3 conversions to decimal ascii 
then you'd see a marked decrease in the overhead of this.  it's not clear 
to me why you need ascii here -- the rest of the existing bsd accounting 
code is not ascii (i'm assuming the purpose of the fork connector is for 
accounting).

-dean
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