ia64: Improve layout of cpuinfo_ia64

Stephane made some measurements on the access-pattern of the cpuinfo_ia64
members and based on those results, this patch reorganizes the structure
for better cache-line sharing.

diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index 72f59bb83741366fc1415848e74f5a6584773083..7f56a498664d7c1e4d448cba6cb4a212904c1b18 100644 (file)
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -91,9 +91,6 @@ handle_IPI (int irq, void *dev_id, struct pt_regs *regs)
        unsigned long *pending_ipis = &__ia64_per_cpu_var(ipi_operation);
        unsigned long ops;
 
-       /* Count this now; we may make a call that never returns. */
-       local_cpu_data->ipi_count++;
-
        mb();   /* Order interrupt and bit testing. */
        while ((ops = xchg(pending_ipis, 0)) != 0) {
                mb();   /* Order bit clearing and data access. */
@@ -338,17 +335,6 @@ smp_call_function (void (*func) (void *info), void *info, int nonatomic, int wai
 }
 EXPORT_SYMBOL(smp_call_function);
 
-void
-smp_do_timer (struct pt_regs *regs)
-{
-       int user = user_mode(regs);
-
-       if (--local_cpu_data->prof_counter <= 0) {
-               local_cpu_data->prof_counter = local_cpu_data->prof_multiplier;
-               update_process_times(user);
-       }
-}
-
 /*
  * this function calls the 'stop' function on all other CPUs in the system.
  */

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index a2d9831faf75e1a5179e376cb84d20f287b8f16e..1db117af80a95386a55547c0d89736f1745dc58a 100644 (file)
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -265,8 +265,6 @@ ia64_sync_itc (unsigned int master)
 static inline void __init
 smp_setup_percpu_timer (void)
 {
-       local_cpu_data->prof_counter = 1;
-       local_cpu_data->prof_multiplier = 1;
 }
 
 static void __init

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index acb30e46ed07a1f3fba69e6a407eb66bb5167d86..744734ecb56252849b46c59dcb135b24e696038d 100644 (file)
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -255,9 +255,13 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
        ia64_do_profile(regs);
 
        while (1) {
-
 #ifdef CONFIG_SMP
-               smp_do_timer(regs);
+               /*
+                * For UP, this is done in do_timer().  Weird, but
+                * fixing that would require updates to all
+                * platforms.
+                */
+               update_process_times(user_mode(regs));
 #endif
                new_itm += local_cpu_data->itm_delta;
 
@@ -280,17 +284,19 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
        }
 
        do {
-           /*
-            * If we're too close to the next clock tick for comfort, we increase the
-            * safety margin by intentionally dropping the next tick(s).  We do NOT update
-            * itm.next because that would force us to call do_timer() which in turn would
-            * let our clock run too fast (with the potentially devastating effect of
-            * losing monotony of time).
-            */
-           while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
-             new_itm += local_cpu_data->itm_delta;
-           ia64_set_itm(new_itm);
-           /* double check, in case we got hit by a (slow) PMI: */
+               /*
+                * If we're too close to the next clock tick for
+                * comfort, we increase the safety margin by
+                * intentionally dropping the next tick(s).  We do NOT
+                * update itm.next because that would force us to call
+                * do_timer() which in turn would let our clock run
+                * too fast (with the potentially devastating effect
+                * of losing monotony of time).
+                */
+               while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
+                       new_itm += local_cpu_data->itm_delta;
+               ia64_set_itm(new_itm);
+               /* double check, in case we got hit by a (slow) PMI: */
        } while (time_after_eq(ia64_get_itc(), new_itm));
        return IRQ_HANDLED;
 }

diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index 0d8d6d5a67577e90cecce866a0c834a35dcec842..5ff52c4eeb727a253380be3351765ccff9f7049b 100644 (file)
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -148,35 +148,35 @@ struct cpuinfo_ia64 {
        __u32 softirq_pending;
        __u64 itm_delta;        /* # of clock cycles between clock ticks */
        __u64 itm_next;         /* interval timer mask value to use for next clock tick */
+       __u64 nsec_per_cyc;     /* (1000000000<<IA64_NSEC_PER_CYC_SHIFT)/itc_freq */
+       __u64 unimpl_va_mask;   /* mask of unimplemented virtual address bits (from PAL) */
+       __u64 unimpl_pa_mask;   /* mask of unimplemented physical address bits (from PAL) */
        __u64 *pgd_quick;
        __u64 *pmd_quick;
        __u64 pgtable_cache_sz;
-       /* CPUID-derived information: */
-       __u64 ppn;
-       __u64 features;
-       __u8 number;
-       __u8 revision;
-       __u8 model;
-       __u8 family;
-       __u8 archrev;
-       char vendor[16];
        __u64 itc_freq;         /* frequency of ITC counter */
        __u64 proc_freq;        /* frequency of processor */
        __u64 cyc_per_usec;     /* itc_freq/1000000 */
-       __u64 nsec_per_cyc;     /* (1000000000<<IA64_NSEC_PER_CYC_SHIFT)/itc_freq */
-       __u64 unimpl_va_mask;   /* mask of unimplemented virtual address bits (from PAL) */
-       __u64 unimpl_pa_mask;   /* mask of unimplemented physical address bits (from PAL) */
        __u64 ptce_base;
        __u32 ptce_count[2];
        __u32 ptce_stride[2];
        struct task_struct *ksoftirqd;  /* kernel softirq daemon for this CPU */
+
 #ifdef CONFIG_SMP
-       int cpu;
        __u64 loops_per_jiffy;
-       __u64 ipi_count;
-       __u64 prof_counter;
-       __u64 prof_multiplier;
+       int cpu;
 #endif
+
+       /* CPUID-derived information: */
+       __u64 ppn;
+       __u64 features;
+       __u8 number;
+       __u8 revision;
+       __u8 model;
+       __u8 family;
+       __u8 archrev;
+       char vendor[16];
+
 #ifdef CONFIG_NUMA
        struct ia64_node_data *node_data;
 #endif