From: Luka Napotnik <luka.napotnik@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: division and cpu usage
Date: Fri, 24 Aug 2007 01:43:30 +0200 [thread overview]
Message-ID: <46CE1BA2.8070200@gmail.com> (raw)
Hello.
I'm new to kernel development and have some questions.
1. Why can't I divide with regular casting to double ((double)a /
(double)b)? It gives me strange errors when compiling:
WARNING: "__divdf3" [/root....] undefined!
WARNING: "__addf3" [/root/...] undefined!
WARNING: "__floatsidf" [/root/...] undefined!
And if I compile with normal integers, I get zero as the result.
2. I'm trying to get the percentage of CPU used for a certain
task_struct and figured the following formula:
(task->utime + task->stime) / jiffies
Before calculating I convert all the variables to jiffies. Is this correct?
Please help.
Greets,
Lukla
next reply other threads:[~2007-08-23 23:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-23 23:43 Luka Napotnik [this message]
2007-08-24 1:04 ` division and cpu usage David Schwartz
2007-08-24 11:34 ` linux-os (Dick Johnson)
2007-08-24 12:46 ` Jan Engelhardt
2007-08-25 23:25 ` Luka Napotnik
2007-08-27 22:07 ` Luka Napotnik
2007-08-28 6:45 ` Jan Engelhardt
2007-08-28 10:41 ` Luka Napotnik
2007-08-28 12:11 ` Jan Engelhardt
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