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From: Frank Salomon <frank.salomon@wincor-nixdorf.com>
To: linux-kernel@vger.kernel.org
Subject: driver or calculation of load average wrong ?
Date: Mon, 11 Oct 2010 08:24:49 +0200	[thread overview]
Message-ID: <4CB2ADB1.6070401@wincor-nixdorf.com> (raw)

Hello All,

I have the following configuration:
- CentOS 5
- kernel 2.6.20.1
- My own driver in a kernel_thread:
		while ( 1 ){
			printk ( KERN_INFO "go sleep, %lu\n", jiffies );
			current -> state = TASK_UNINTERRUPTIBLE;
			schedule_timeout ( msecs_to_jiffies(4000) );
			printk ( KERN_INFO "wakeup, %lu\n", jiffies );
		}

Each time I load the driver, the load average in /proc/loadavg reached:
	$ cat /proc/loadavg
	0.99 0.62 0.26 1/47 2868
Without my driver:
	$ cat /proc/loadavg
	0.03 0.03 0.00 1/47 2867

I changed nr_active(void) in kernel/sched.c:
unsigned long nr_active(void)
{
          unsigned long i, running = 0, uninterruptible = 0;

          for_each_online_cpu(i) {
                  running += cpu_rq(i)->nr_running;
                  uninterruptible += cpu_rq(i)->nr_uninterruptible;
          }

          if (unlikely((long)uninterruptible < 0))
                  uninterruptible = 0;

// original:     return running + uninterruptible;
          return running;
}

Driver loaded or not:
	$ cat /proc/loadavg
	0.03 0.03 0.00 1/47 2867

Any help or comments would be really great?

Best regards, thanks, Frank
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             reply	other threads:[~2010-10-11  6:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-11  6:24 Frank Salomon [this message]
2010-10-11  7:40 ` Alexander Clouter
2010-10-11 19:39 ` Greg KH
  -- strict thread matches above, loose matches on Subject: below --
2010-10-07 22:48 [PATCH] dma/timberdale: simplify conditional Nicolas Kaiser
2010-10-08 12:22 ` Jack Stone
2010-10-08 12:25   ` Jack Stone
2010-10-08 12:48     ` driver or calculation of load average wrong ? Frank Salomon

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