Group the hot path members of struct clocksource together so we have a better cache line footprint. Make it cacheline aligned. Signed-off-by: Thomas Gleixner Eric Dumazet --- include/linux/clocksource.h | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) Index: linux-2.6-tip/include/linux/clocksource.h =================================================================== --- linux-2.6-tip.orig/include/linux/clocksource.h +++ linux-2.6-tip/include/linux/clocksource.h @@ -159,42 +159,38 @@ extern u64 timecounter_cyc2time(struct t */ struct clocksource { /* - * First part of structure is read mostly + * Hotpath data, fits in a single cache line when the + * clocksource itself is cacheline aligned. */ - const char *name; - struct list_head list; - int rating; cycle_t (*read)(struct clocksource *cs); - int (*enable)(struct clocksource *cs); - void (*disable)(struct clocksource *cs); + cycle_t cycle_last; cycle_t mask; u32 mult; u32 shift; u64 max_idle_ns; - unsigned long flags; - cycle_t (*vread)(void); - void (*suspend)(struct clocksource *cs); - void (*resume)(struct clocksource *cs); + #ifdef CONFIG_IA64 void *fsys_mmio; /* used by fsyscall asm code */ #define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr)) #else #define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0) #endif - - /* - * Second part is written at each timer interrupt - * Keep it in a different cache line to dirty no - * more than one cache line. - */ - cycle_t cycle_last ____cacheline_aligned_in_smp; + const char *name; + struct list_head list; + int rating; + cycle_t (*vread)(void); + int (*enable)(struct clocksource *cs); + void (*disable)(struct clocksource *cs); + unsigned long flags; + void (*suspend)(struct clocksource *cs); + void (*resume)(struct clocksource *cs); #ifdef CONFIG_CLOCKSOURCE_WATCHDOG /* Watchdog related data, used by the framework */ struct list_head wd_list; cycle_t wd_last; #endif -}; +} ____cacheline_aligned; /* * Clock source flags bits:: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/