From 314ff52727fe94dfbe07f3a9a489ab3ca8d8df5a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 27 Jul 2011 20:46:25 -0700 Subject: [PATCH] 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 --- arch/sparc/kernel/pcr.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) 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); } -- 2.20.1