linux-kernel - Re: Weird wasting of time between ioctl() and ioctl dispatcher

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Message-ID: <p73r6vpdu1i.fsf@bingen.suse.de>
Date:	27 Nov 2006 12:10:33 +0100
From:	Andi Kleen <ak@...e.de>
To:	"Cestonaro, Thilo (external)" 
	<Thilo.Cestonaro.external@...itsu-siemens.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Weird wasting of time between ioctl() and ioctl dispatcher

"Cestonaro, Thilo \(external\)"    <Thilo.Cestonaro.external@...itsu-siemens.com> writes:

> I'm a developer for Fujitsu Siemens Computers, working on a program which has it's own kernel modules and userland components.
> Now cause the program should be released we have done some testing and during this testphase a wierd wasting of time occured
> during the call of the ioctl() in the userland component and the actuall entering of the dispatcher function in the module.
> It takes 3 min. until the call at last enters my dispatcher. 

Something else is holding the big kernel lock for that long. Most likely
it's your own code. Consider using a ->unlocked_ioctl

-Andi
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