From: David S. Miller <davem@davemloft.net>
Date: Thu, 28 Jul 2011 03:46:25 +0000 (-0700)
Subject: sparc: Don't do expensive hypervisor PCR write unless necessary.
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=314ff52727fe94dfbe07f3a9a489ab3ca8d8df5a;p=linux-beck.git

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 <davem@davemloft.net>
---

diff --git a/arch/sparc/kernel/pcr.c b/arch/sparc/kernel/pcr.c
index 8ac23e660080..878c6824c732 100644
--- 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);
 }