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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] use atomic_t type for system wide credit scheduler statistics
Keir Fraser wrote: On 09/03/2009 08:30, "Yang, Xiaowei" <xiaowei.yang@xxxxxxxxx> wrote:Keir Fraser wrote:Not while csched stats are enabled by default. They get cranked all over the place. How much does this race matter? We probably just lose a few increments?Yes. The higher frequency the count is updated, the more increments lost can we see - comparing to atomic version, counts like "vcpu_check" and "scheduele" lose increments very obviously due to race.The best thing to do would be to move the stats into perfc_defn.h, don't you think? The CSCHED_* macro wrappers could be kept but wrap the existing common mechanism for perf counters. Agree. updated version attached. Signed-off-by: Xiaowei Yang <xiaowei.yang@xxxxxxxxx> diff -r 227228b7dce4 xen/common/sched_credit.c
--- a/xen/common/sched_credit.c Mon Mar 09 03:20:57 2009 +0800
+++ b/xen/common/sched_credit.c Mon Mar 09 04:08:51 2009 +0800
@@ -25,7 +25,7 @@
/*
* CSCHED_STATS
*
- * Manage very basic counters and stats.
+ * Manage very basic per-vCPU counters and stats.
*
* Useful for debugging live systems. The stats are displayed
* with runq dumps ('r' on the Xen console).
@@ -77,85 +77,9 @@
/*
* Stats
*/
+#define CSCHED_STAT_CRANK(_X) (perfc_incr(_X))
+
#ifdef CSCHED_STATS
-
-#define CSCHED_STAT(_X) (csched_priv.stats._X)
-#define CSCHED_STAT_DEFINE(_X) uint32_t _X;
-#define CSCHED_STAT_PRINTK(_X) \
- do \
- { \
- printk("\t%-30s = %u\n", #_X, CSCHED_STAT(_X)); \
- } while ( 0 );
-
-/*
- * Try and keep often cranked stats on top so they'll fit on one
- * cache line.
- */
-#define CSCHED_STATS_EXPAND_SCHED(_MACRO) \
- _MACRO(schedule) \
- _MACRO(acct_run) \
- _MACRO(acct_no_work) \
- _MACRO(acct_balance) \
- _MACRO(acct_reorder) \
- _MACRO(acct_min_credit) \
- _MACRO(acct_vcpu_active) \
- _MACRO(acct_vcpu_idle) \
- _MACRO(vcpu_sleep) \
- _MACRO(vcpu_wake_running) \
- _MACRO(vcpu_wake_onrunq) \
- _MACRO(vcpu_wake_runnable) \
- _MACRO(vcpu_wake_not_runnable) \
- _MACRO(vcpu_park) \
- _MACRO(vcpu_unpark) \
- _MACRO(tickle_local_idler) \
- _MACRO(tickle_local_over) \
- _MACRO(tickle_local_under) \
- _MACRO(tickle_local_other) \
- _MACRO(tickle_idlers_none) \
- _MACRO(tickle_idlers_some) \
- _MACRO(load_balance_idle) \
- _MACRO(load_balance_over) \
- _MACRO(load_balance_other) \
- _MACRO(steal_trylock_failed) \
- _MACRO(steal_peer_idle) \
- _MACRO(migrate_queued) \
- _MACRO(migrate_running) \
- _MACRO(dom_init) \
- _MACRO(dom_destroy) \
- _MACRO(vcpu_init) \
- _MACRO(vcpu_destroy)
-
-#ifndef NDEBUG
-#define CSCHED_STATS_EXPAND_CHECKS(_MACRO) \
- _MACRO(vcpu_check)
-#else
-#define CSCHED_STATS_EXPAND_CHECKS(_MACRO)
-#endif
-
-#define CSCHED_STATS_EXPAND(_MACRO) \
- CSCHED_STATS_EXPAND_CHECKS(_MACRO) \
- CSCHED_STATS_EXPAND_SCHED(_MACRO)
-
-#define CSCHED_STATS_RESET() \
- do \
- { \
- memset(&csched_priv.stats, 0, sizeof(csched_priv.stats)); \
- } while ( 0 )
-
-#define CSCHED_STATS_DEFINE() \
- struct \
- { \
- CSCHED_STATS_EXPAND(CSCHED_STAT_DEFINE) \
- } stats;
-
-#define CSCHED_STATS_PRINTK() \
- do \
- { \
- printk("stats:\n"); \
- CSCHED_STATS_EXPAND(CSCHED_STAT_PRINTK) \
- } while ( 0 )
-
-#define CSCHED_STAT_CRANK(_X) (CSCHED_STAT(_X)++)
#define CSCHED_VCPU_STATS_RESET(_V) \
do \
@@ -170,10 +93,6 @@
#else /* CSCHED_STATS */
-#define CSCHED_STATS_RESET() do {} while ( 0 )
-#define CSCHED_STATS_DEFINE()
-#define CSCHED_STATS_PRINTK() do {} while ( 0 )
-#define CSCHED_STAT_CRANK(_X) do {} while ( 0 )
#define CSCHED_VCPU_STATS_RESET(_V) do {} while ( 0 )
#define CSCHED_VCPU_STAT_CRANK(_V, _X) do {} while ( 0 )
#define CSCHED_VCPU_STAT_SET(_V, _X, _Y) do {} while ( 0 )
@@ -239,7 +158,6 @@ struct csched_private {
uint32_t credit;
int credit_balance;
uint32_t runq_sort;
- CSCHED_STATS_DEFINE()
};
@@ -1331,8 +1249,6 @@ csched_dump(void)
cpumask_scnprintf(idlers_buf, sizeof(idlers_buf), csched_priv.idlers);
printk("idlers: %s\n", idlers_buf);
- CSCHED_STATS_PRINTK();
-
printk("active vcpus:\n");
loop = 0;
list_for_each( iter_sdom, &csched_priv.active_sdom )
@@ -1363,7 +1279,6 @@ csched_init(void)
csched_priv.credit = 0U;
csched_priv.credit_balance = 0;
csched_priv.runq_sort = 0U;
- CSCHED_STATS_RESET();
}
/* Tickers cannot be kicked until SMP subsystem is alive. */
diff -r 227228b7dce4 xen/include/xen/perfc_defn.h
--- a/xen/include/xen/perfc_defn.h Mon Mar 09 03:20:57 2009 +0800
+++ b/xen/include/xen/perfc_defn.h Mon Mar 09 04:04:01 2009 +0800
@@ -16,6 +16,40 @@ PERFCOUNTER(sched_run, "sch
PERFCOUNTER(sched_run, "sched: runs through scheduler")
PERFCOUNTER(sched_ctx, "sched: context switches")
+PERFCOUNTER(vcpu_check, "csched: vcpu_check")
+PERFCOUNTER(schedule, "csched: schedule")
+PERFCOUNTER(acct_run, "csched: acct_run")
+PERFCOUNTER(acct_no_work, "csched: acct_no_work")
+PERFCOUNTER(acct_balance, "csched: acct_balance")
+PERFCOUNTER(acct_reorder, "csched: acct_reorder")
+PERFCOUNTER(acct_min_credit, "csched: acct_min_credit")
+PERFCOUNTER(acct_vcpu_active, "csched: acct_vcpu_active")
+PERFCOUNTER(acct_vcpu_idle, "csched: acct_vcpu_idle")
+PERFCOUNTER(vcpu_sleep, "csched: vcpu_sleep")
+PERFCOUNTER(vcpu_wake_running, "csched: vcpu_wake_running")
+PERFCOUNTER(vcpu_wake_onrunq, "csched: vcpu_wake_onrunq")
+PERFCOUNTER(vcpu_wake_runnable, "csched: vcpu_wake_runnable")
+PERFCOUNTER(vcpu_wake_not_runnable, "csched: vcpu_wake_not_runnable")
+PERFCOUNTER(vcpu_park, "csched: vcpu_park")
+PERFCOUNTER(vcpu_unpark, "csched: vcpu_unpark")
+PERFCOUNTER(tickle_local_idler, "csched: tickle_local_idler")
+PERFCOUNTER(tickle_local_over, "csched: tickle_local_over")
+PERFCOUNTER(tickle_local_under, "csched: tickle_local_under")
+PERFCOUNTER(tickle_local_other, "csched: tickle_local_other")
+PERFCOUNTER(tickle_idlers_none, "csched: tickle_idlers_none")
+PERFCOUNTER(tickle_idlers_some, "csched: tickle_idlers_some")
+PERFCOUNTER(load_balance_idle, "csched: load_balance_idle")
+PERFCOUNTER(load_balance_over, "csched: load_balance_over")
+PERFCOUNTER(load_balance_other, "csched: load_balance_other")
+PERFCOUNTER(steal_trylock_failed, "csched: steal_trylock_failed")
+PERFCOUNTER(steal_peer_idle, "csched: steal_peer_idle")
+PERFCOUNTER(migrate_queued, "csched: migrate_queued")
+PERFCOUNTER(migrate_running, "csched: migrate_running")
+PERFCOUNTER(dom_init, "csched: dom_init")
+PERFCOUNTER(dom_destroy, "csched: dom_destroy")
+PERFCOUNTER(vcpu_init, "csched: vcpu_init")
+PERFCOUNTER(vcpu_destroy, "csched: vcpu_destroy")
+
PERFCOUNTER(need_flush_tlb_flush, "PG_need_flush tlb flushes")
/*#endif*/ /* __XEN_PERFC_DEFN_H__ */
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