[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20081110160409.GB3933@in.ibm.com>
Date: Mon, 10 Nov 2008 21:34:09 +0530
From: Bharata B Rao <bharata@...ux.vnet.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: linux-kernel@...r.kernel.org,
Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
Ingo Molnar <mingo@...e.hu>,
Dhaval Giani <dhaval@...ux.vnet.ibm.com>
Subject: Re: [PATCH -v2] sched: Include group statistics in
/proc/sched_debug
On Mon, Nov 10, 2008 at 10:30:07AM +0100, Peter Zijlstra wrote:
> On Mon, 2008-11-10 at 14:53 +0530, Bharata B Rao wrote:
>
> > An extract of /proc/sched_debug showing group stats obtained from
> > this patch:
> >
> > group[1]:/3/a/1
> > .se->exec_start : 256484.781577
> > .se->vruntime : 12868.176994
> > .se->sum_exec_runtime : 3243.669709
> > .se->wait_start : 0.000000
> > .se->sleep_start : 0.000000
> > .se->block_start : 0.000000
> > .se->sleep_max : 0.000000
> > .se->block_max : 0.000000
> > .se->exec_max : 1.002095
> > .se->slice_max : 13.997073
> > .se->wait_max : 67.978322
> > .se->wait_sum : 7141.676906
> > .se->wait_count : 203
> > .se->load.weight : 255
>
> Why not simply add them to the cfs_rq[n]:/path sections we already have?
Makes sense. Here is the updated patch which puts group statistics
under cfs_rq[n]:/path section as you suggest.
Include group statistics in /proc/sched_debug.
Since the statistics of a group entity isn't exported directly from the
kernel, it becomes difficult to obtain some of the group statistics.
For example, the current method to obtain exec time of a group entity
is not always accurate. One has to read the exec times of all
the tasks(/proc/<pid>/sched) in the group and add them. This method
fails (or becomes difficult) if we want to collect stats of a group over
a duration where tasks get created and terminated.
This patch makes it easier to obtain group stats by directly including
them in /proc/sched_debug. Stats like group exec time would help user
programs (like LTP) to accurately measure the group fairness.
Signed-off-by: Bharata B Rao <bharata@...ux.vnet.ibm.com>
CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Ingo Molnar <mingo@...e.hu>
CC: Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
---
kernel/sched_debug.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -53,6 +53,40 @@ static unsigned long nsec_low(unsigned l
#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void print_cfs_group_stats(struct seq_file *m, int cpu,
+ struct task_group *tg)
+{
+ struct sched_entity *se = tg->se[cpu];
+ if (!se)
+ return;
+
+#define P(F) \
+ SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
+#define PN(F) \
+ SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
+
+ PN(se->exec_start);
+ PN(se->vruntime);
+ PN(se->sum_exec_runtime);
+#ifdef CONFIG_SCHEDSTATS
+ PN(se->wait_start);
+ PN(se->sleep_start);
+ PN(se->block_start);
+ PN(se->sleep_max);
+ PN(se->block_max);
+ PN(se->exec_max);
+ PN(se->slice_max);
+ PN(se->wait_max);
+ PN(se->wait_sum);
+ P(se->wait_count);
+#endif
+ P(se->load.weight);
+#undef PN
+#undef P
+}
+#endif
+
static void
print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
{
@@ -186,6 +220,7 @@ void print_cfs_rq(struct seq_file *m, in
#ifdef CONFIG_SMP
SEQ_printf(m, " .%-30s: %lu\n", "shares", cfs_rq->shares);
#endif
+ print_cfs_group_stats(m, cpu, cfs_rq->tg);
#endif
}
@@ -271,7 +306,7 @@ static int sched_debug_show(struct seq_f
u64 now = ktime_to_ns(ktime_get());
int cpu;
- SEQ_printf(m, "Sched Debug Version: v0.07, %s %.*s\n",
+ SEQ_printf(m, "Sched Debug Version: v0.08, %s %.*s\n",
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
--
An example output of group stats from /proc/sched_debug:
cfs_rq[3]:/3/a/1
.exec_clock : 89.598007
.MIN_vruntime : 0.000001
.min_vruntime : 256300.970506
.max_vruntime : 0.000001
.spread : 0.000000
.spread0 : -25373.372248
.nr_running : 0
.load : 0
.yld_exp_empty : 0
.yld_act_empty : 0
.yld_both_empty : 0
.yld_count : 4474
.sched_switch : 0
.sched_count : 40507
.sched_goidle : 12686
.ttwu_count : 15114
.ttwu_local : 11950
.bkl_count : 67
.nr_spread_over : 0
.shares : 0
.se->exec_start : 113676.727170
.se->vruntime : 1592.612714
.se->sum_exec_runtime : 89.598007
.se->wait_start : 0.000000
.se->sleep_start : 0.000000
.se->block_start : 0.000000
.se->sleep_max : 0.000000
.se->block_max : 0.000000
.se->exec_max : 1.000282
.se->slice_max : 1.999750
.se->wait_max : 54.981093
.se->wait_sum : 217.610521
.se->wait_count : 50
.se->load.weight : 2
Regards,
Bharata.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists