[PATCH] Re: /proc/uptime idle counter remains at 0

From: Michael Abbott
Date: Mon May 18 2009 - 09:23:30 EST


Resending this patch, as it doesn't seem to have made it into the kernel
(and this feature really doesn't need to be left broken).

---------- Forwarded message ----------
Date: Mon, 11 May 2009 10:07:14 +0100 (BST)
From: Michael Abbott <michael@xxxxxxxxxxxxxxx>
To: Jan Engelhardt <jengelh@xxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>,
Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
Subject: Re: [PATCH] Re: /proc/uptime idle counter remains at 0

On Mon, 11 May 2009, Michael Abbott wrote:
> So as a simple solution, I've attached a patch where I just copy the
> idle field processing from fs/proc/stat.c. I expect that on a
> multi-processor machine things may not be quite so simple -- as up time
> is in elapsed wall-clock time, then so should idle time be, so we
> probably need to also divide by the number of processors. Afraid I
> don't have a multiprocessor test system, and /proc/stat seems ok, so
> I've not made this refinement.

To hopefully help, I've rebased the patch onto current git
(fs/proc/uptime.c has undergone some unrelated changes).


Date: Mon, 11 May 2009 07:14:19 +0100
Subject: [PATCH] Fix idle time field in /proc/uptime

Git commit 79741dd changes idle cputime accounting, but unfortunately
the /proc/uptime file hasn't caught up. Here the idle time calculation
from /proc/stat is copied over.

Signed-off-by: Michael Abbott <michael.abbott@xxxxxxxxxxxxx>
---
fs/proc/uptime.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
index 0c10a0b..0f43395 100644
--- a/fs/proc/uptime.c
+++ b/fs/proc/uptime.c
@@ -4,13 +4,19 @@
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/time.h>
+#include <linux/kernel_stat.h>
#include <asm/cputime.h>

static int uptime_proc_show(struct seq_file *m, void *v)
{
struct timespec uptime;
struct timespec idle;
- cputime_t idletime = cputime_add(init_task.utime, init_task.stime);
+ int len, i;
+ cputime_t idletime = 0;
+
+ for_each_possible_cpu(i)
+ idletime = cputime64_add(idletime, kstat_cpu(i).cpustat.idle);
+ idletime = cputime64_to_clock_t(idletime);

do_posix_clock_monotonic_gettime(&uptime);
monotonic_to_bootbased(&uptime);
--
1.6.1.3

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