[Patch 4/9] Block I/O accounting collection

[Shailabh Nagar <nagar@watson.ibm.com>]

delayacct-blkio-collect.patch

Collect per-task block I/O delay statistics.

Unlike earlier iterations of the delay accounting
patches, now delays are only collected for the actual
I/O waits rather than try and cover the delays seen in 
I/O submission paths.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>

 kernel/sched.c |    5 +++++
 1 files changed, 5 insertions(+)

Index: linux-2.6.16-rc5/kernel/sched.c
===================================================================
--- linux-2.6.16-rc5.orig/kernel/sched.c	2006-03-11 07:41:32.000000000 -0500
+++ linux-2.6.16-rc5/kernel/sched.c	2006-03-11 07:41:39.000000000 -0500
@@ -49,6 +49,7 @@
 #include <linux/syscalls.h>
 #include <linux/times.h>
 #include <linux/acct.h>
+#include <linux/delayacct.h>
 #include <asm/tlb.h>
 
 #include <asm/unistd.h>
@@ -4117,9 +4118,11 @@ void __sched io_schedule(void)
 {
 	struct runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id());
 
+	delayacct_blkio_start();
 	atomic_inc(&rq->nr_iowait);
 	schedule();
 	atomic_dec(&rq->nr_iowait);
+	delayacct_blkio_end();
 }
 
 EXPORT_SYMBOL(io_schedule);
@@ -4129,9 +4132,11 @@ long __sched io_schedule_timeout(long ti
 	struct runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id());
 	long ret;
 
+	delayacct_blkio_start();
 	atomic_inc(&rq->nr_iowait);
 	ret = schedule_timeout(timeout);
 	atomic_dec(&rq->nr_iowait);
+	delayacct_blkio_end();
 	return ret;
 }
 


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