sparc: Don't do expensive hypervisor PCR write unless necessary.

The hypervisor call is only necessary if hypervisor events are being requested. So if we're not tracking hypervisor events, simply do a direct register write. Signed-off-by: David S. Miller <[email protected]>
teemow · Jul 28, 2011 · 314ff52 · 314ff52
1 parent 15e3608
commit 314ff52
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/arch/sparc/kernel/pcr.c b/arch/sparc/kernel/pcr.c
@@ -80,8 +80,11 @@ static void n2_pcr_write(u64 val)
 {
 	unsigned long ret;
 
-	ret = sun4v_niagara2_setperf(HV_N2_PERF_SPARC_CTL, val);
-	if (ret != HV_EOK)
+	if (val & PCR_N2_HTRACE) {
+		ret = sun4v_niagara2_setperf(HV_N2_PERF_SPARC_CTL, val);
+		if (ret != HV_EOK)
+			write_pcr(val);
+	} else
 		write_pcr(val);
 }