51 lines
1.9 KiB
Diff
51 lines
1.9 KiB
Diff
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References: bsc#970135
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# Commit b64438c7c1495a7580d1bb9d8ba644f3705e1ffb
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# Date 2016-06-14 15:08:47 +0200
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# Author Jan Beulich <jbeulich@suse.com>
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# Committer Jan Beulich <jbeulich@suse.com>
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x86/time: use correct (local) time stamp in constant-TSC calibration fast path
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This looks like a copy and paste mistake in commit 1b6a99892d ("x86:
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Simpler time handling when TSC is constant across all power saving
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states"), responsible for occasional many-microsecond cross-CPU skew of
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what NOW() returns.
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Also improve the correlation between local TSC and stime stamps
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obtained at the end of the two calibration handlers: Compute the stime
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one from the TSC one, instead of doing another rdtsc() for that
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compuation.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
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--- a/xen/arch/x86/time.c
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+++ b/xen/arch/x86/time.c
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@@ -998,7 +998,7 @@ static void local_time_calibration(void)
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/* Atomically read cpu_calibration struct and write cpu_time struct. */
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local_irq_disable();
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t->local_tsc_stamp = c->local_tsc_stamp;
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- t->stime_local_stamp = c->stime_master_stamp;
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+ t->stime_local_stamp = c->stime_local_stamp;
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t->stime_master_stamp = c->stime_master_stamp;
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local_irq_enable();
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update_vcpu_system_time(current);
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@@ -1275,7 +1275,7 @@ static void time_calibration_tsc_rendezv
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}
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c->local_tsc_stamp = rdtsc();
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- c->stime_local_stamp = get_s_time();
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+ c->stime_local_stamp = get_s_time_fixed(c->local_tsc_stamp);
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c->stime_master_stamp = r->master_stime;
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raise_softirq(TIME_CALIBRATE_SOFTIRQ);
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@@ -1305,7 +1305,7 @@ static void time_calibration_std_rendezv
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}
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c->local_tsc_stamp = rdtsc();
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- c->stime_local_stamp = get_s_time();
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+ c->stime_local_stamp = get_s_time_fixed(c->local_tsc_stamp);
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c->stime_master_stamp = r->master_stime;
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raise_softirq(TIME_CALIBRATE_SOFTIRQ);
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