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From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH] trace-cmd library: Do not record TSC frac bits if scaling is default
Date: Fri, 10 Dec 2021 13:55:08 +0200	[thread overview]
Message-ID: <20211210115508.103569-1-tz.stoyanov@gmail.com> (raw)

Guest's TSC fraction bits have sens only if there is TSC scaling. In
case of default value for TSC scaling, fraction bits should not be used
in TSC guest clock calculation.

Fixes: https://lore.kernel.org/linux-trace-devel/20211014150204.2485499-3-tz.stoyanov@gmail.com/
	(trace-cmd library: Extend host-guest time sync with fraction bits)

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-timesync-kvm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/trace-cmd/trace-timesync-kvm.c b/lib/trace-cmd/trace-timesync-kvm.c
index 8d531922..12a22d4c 100644
--- a/lib/trace-cmd/trace-timesync-kvm.c
+++ b/lib/trace-cmd/trace-timesync-kvm.c
@@ -415,7 +415,7 @@ static int kvm_clock_host(struct tracecmd_time_sync *tsync,
 			kvm_scaling = 1;
 	}
 
-	if (kvm->vcpu_frac && kvm->vcpu_frac[cpu])
+	if (kvm->vcpu_frac && kvm->vcpu_frac[cpu] && kvm_scaling != 1)
 		ret = read_ll_from_file(kvm->vcpu_frac[cpu], &kvm_frac);
 	msg = (char *)&packet;
 	size = sizeof(packet);
-- 
2.33.1


             reply	other threads:[~2021-12-10 11:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-10 11:55 Tzvetomir Stoyanov (VMware) [this message]
2022-02-16 15:43 ` [PATCH] trace-cmd library: Do not record TSC frac bits if scaling is default Tzvetomir Stoyanov
2022-02-16 16:47   ` Steven Rostedt

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