powerpc/pseries: Add dispatch dispersion statistics

PHYP tells us how often a shared processor dispatch changed physical cpus.
This can highlight performance problems caused by the hypervisor.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 17 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h
index 68235f7e4a8f..d2a65e8ca6ae 100644
--- a/arch/powerpc/include/asm/lppaca.h
+++ b/arch/powerpc/include/asm/lppaca.h
@@ -125,7 +125,7 @@ struct lppaca {
         // NOTE: This value will ALWAYS be zero for dedicated processors and
         // will NEVER be zero for shared processors (ie, initialized to a 1).
         volatile u32 yield_count;       // PLIC increments each dispatchx00-x03
-        u32 reserved6;
+        volatile u32 dispersion_count;  // dispatch changed phys cpu    x04-x07
         volatile u64 cmo_faults;        // CMO page fault count         x08-x0F
         volatile u64 cmo_fault_time;    // CMO page fault time          x10-x17
         u8      reserved7[104];         // Reserved                     x18-x7F
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 182e0f642f36..78b3f7840ade 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -434,6 +434,21 @@ static void pseries_cmo_data(struct seq_file *m)
         seq_printf(m, "cmo_page_size=%lu\n", cmo_get_page_size());
 }
 
+static void splpar_dispatch_data(struct seq_file *m)
+{
+        int cpu;
+        unsigned long dispatches = 0;
+        unsigned long dispatch_dispersions = 0;
+
+        for_each_possible_cpu(cpu) {
+                dispatches += lppaca[cpu].yield_count;
+                dispatch_dispersions += lppaca[cpu].dispersion_count;
+        }
+
+        seq_printf(m, "dispatches=%lu\n", dispatches);
+        seq_printf(m, "dispatch_dispersions=%lu\n", dispatch_dispersions);
+}
+
 static int pseries_lparcfg_data(struct seq_file *m, void *v)
 {
         int partition_potential_processors;
@@ -460,6 +475,7 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
                 parse_ppp_data(m);
                 parse_mpp_data(m);
                 pseries_cmo_data(m);
+                splpar_dispatch_data(m);
 
                 seq_printf(m, "purr=%ld\n", get_purr());
         } else {                /* non SPLPAR case */