From f8eca41f0afcc7042dc3398c8ba5878c59b1cf1b Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 20 Aug 2008 17:02:21 -0700 Subject: [PATCH] xen: measure how long spinlocks spend blocking Measure how long spinlocks spend blocked. Also rename some fields to be more consistent. Signed-off-by: Jeremy Fitzhardinge Acked-by: Jan Beulich Signed-off-by: Ingo Molnar --- arch/x86/xen/spinlock.c | 62 ++++++++++++++++++++++++++++------------- 1 file changed, 42 insertions(+), 20 deletions(-) diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index e6061f2e64f..d072823bc06 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -29,12 +29,14 @@ static struct xen_spinlock_stats u32 released_slow; u32 released_slow_kicked; -#define HISTO_BUCKETS 20 - u32 histo_spin_fast[HISTO_BUCKETS+1]; - u32 histo_spin[HISTO_BUCKETS+1]; - - u64 spinning_time; - u64 total_time; +#define HISTO_BUCKETS 30 + u32 histo_spin_total[HISTO_BUCKETS+1]; + u32 histo_spin_spinning[HISTO_BUCKETS+1]; + u32 histo_spin_blocked[HISTO_BUCKETS+1]; + + u64 time_total; + u64 time_spinning; + u64 time_blocked; } spinlock_stats; static u8 zero_stats; @@ -70,20 +72,28 @@ static void __spin_time_accum(u64 delta, u32 *array) array[HISTO_BUCKETS]++; } -static inline void spin_time_accum_fast(u64 start) +static inline void spin_time_accum_spinning(u64 start) +{ + u32 delta = xen_clocksource_read() - start; + + __spin_time_accum(delta, spinlock_stats.histo_spin_spinning); + spinlock_stats.time_spinning += delta; +} + +static inline void spin_time_accum_total(u64 start) { u32 delta = xen_clocksource_read() - start; - __spin_time_accum(delta, spinlock_stats.histo_spin_fast); - spinlock_stats.spinning_time += delta; + __spin_time_accum(delta, spinlock_stats.histo_spin_total); + spinlock_stats.time_total += delta; } -static inline void spin_time_accum(u64 start) +static inline void spin_time_accum_blocked(u64 start) { u32 delta = xen_clocksource_read() - start; - __spin_time_accum(delta, spinlock_stats.histo_spin); - spinlock_stats.total_time += delta; + __spin_time_accum(delta, spinlock_stats.histo_spin_blocked); + spinlock_stats.time_blocked += delta; } #else /* !CONFIG_XEN_DEBUG_FS */ #define TIMEOUT (1 << 10) @@ -94,10 +104,13 @@ static inline u64 spin_time_start(void) return 0; } -static inline void spin_time_accum_fast(u64 start) +static inline void spin_time_accum_total(u64 start) +{ +} +static inline void spin_time_accum_spinning(u64 start) { } -static inline void spin_time_accum(u64 start) +static inline void spin_time_accum_blocked(u64 start) { } #endif /* CONFIG_XEN_DEBUG_FS */ @@ -175,11 +188,14 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl int irq = __get_cpu_var(lock_kicker_irq); int ret; unsigned long flags; + u64 start; /* If kicker interrupts not initialized yet, just spin */ if (irq == -1) return 0; + start = spin_time_start(); + /* announce we're spinning */ prev = spinning_lock(xl); @@ -230,6 +246,8 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl out: raw_local_irq_restore(flags); unspinning_lock(xl, prev); + spin_time_accum_blocked(start); + return ret; } @@ -262,12 +280,12 @@ static inline void __xen_spin_lock(struct raw_spinlock *lock, bool irq_enable) : "1" (1) : "memory"); - spin_time_accum_fast(start_spin_fast); + spin_time_accum_spinning(start_spin_fast); } while (unlikely(oldval != 0 && (TIMEOUT == ~0 || !xen_spin_lock_slow(lock, irq_enable)))); - spin_time_accum(start_spin); + spin_time_accum_total(start_spin); } static void xen_spin_lock(struct raw_spinlock *lock) @@ -385,14 +403,18 @@ static int __init xen_spinlock_debugfs(void) &spinlock_stats.released_slow_kicked); debugfs_create_u64("time_spinning", 0444, d_spin_debug, - &spinlock_stats.spinning_time); + &spinlock_stats.time_spinning); + debugfs_create_u64("time_blocked", 0444, d_spin_debug, + &spinlock_stats.time_blocked); debugfs_create_u64("time_total", 0444, d_spin_debug, - &spinlock_stats.total_time); + &spinlock_stats.time_total); xen_debugfs_create_u32_array("histo_total", 0444, d_spin_debug, - spinlock_stats.histo_spin, HISTO_BUCKETS + 1); + spinlock_stats.histo_spin_total, HISTO_BUCKETS + 1); xen_debugfs_create_u32_array("histo_spinning", 0444, d_spin_debug, - spinlock_stats.histo_spin_fast, HISTO_BUCKETS + 1); + spinlock_stats.histo_spin_spinning, HISTO_BUCKETS + 1); + xen_debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug, + spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1); return 0; } -- 2.41.0