s390/vtime: correct scaled cputime of partially idle CPUs
The calculation for the SMT scaling factor for a hardware thread
which has been partially idle needs to disregard the cycles spent
by the other threads of the core while the thread is idle.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 09b039d..582fe44 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -733,6 +733,14 @@
stg %r3,__SF_EMPTY(%r15)
larl %r1,.Lpsw_idle_lpsw+4
stg %r1,__SF_EMPTY+8(%r15)
+#ifdef CONFIG_SMP
+ larl %r1,smp_cpu_mtid
+ llgf %r1,0(%r1)
+ ltgr %r1,%r1
+ jz .Lpsw_idle_stcctm
+ .insn rsy,0xeb0000000017,%r1,5,__SF_EMPTY+16(%r15)
+.Lpsw_idle_stcctm:
+#endif
STCK __CLOCK_IDLE_ENTER(%r2)
stpt __TIMER_IDLE_ENTER(%r2)
.Lpsw_idle_lpsw:
@@ -1159,7 +1167,27 @@
jhe 1f
mvc __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
mvc __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r2)
-1: # account system time going idle
+1: # calculate idle cycles
+#ifdef CONFIG_SMP
+ clg %r9,BASED(.Lcleanup_idle_insn)
+ jl 3f
+ larl %r1,smp_cpu_mtid
+ llgf %r1,0(%r1)
+ ltgr %r1,%r1
+ jz 3f
+ .insn rsy,0xeb0000000017,%r1,5,__SF_EMPTY+80(%r15)
+ larl %r3,mt_cycles
+ ag %r3,__LC_PERCPU_OFFSET
+ la %r4,__SF_EMPTY+16(%r15)
+2: lg %r0,0(%r3)
+ slg %r0,0(%r4)
+ alg %r0,64(%r4)
+ stg %r0,0(%r3)
+ la %r3,8(%r3)
+ la %r4,8(%r4)
+ brct %r1,2b
+#endif
+3: # account system time going idle
lg %r9,__LC_STEAL_TIMER
alg %r9,__CLOCK_IDLE_ENTER(%r2)
slg %r9,__LC_LAST_UPDATE_CLOCK