Thread (5 messages) 5 messages, 2 authors, 27d ago

Re: [PATCH] powerpc/vtime: Initialize starttime at boot for native accounting

From: Shrikanth Hegde <hidden>
Date: 2026-06-05 03:03:23

Hi Christophe. Thanks for taking a look and review.

On 6/4/26 8:42 PM, Christophe Leroy (CS GROUP) wrote:
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Also, does this warrant Fixes tag? I found these two likely candidates.
Likely this issues exists since beginning.
c223c90386bc powerpc32: provide VIRT_CPU_ACCOUNTING
You say system has 240 CPU so I suppose this is not ppc32. That commit 
wsa not supposed to change anything for ppc64, did you identify 
anything special in that commit related to ppc64 ?
Yes. this was ppc64.
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b38a181c11d0 powerpc/time: isolate scaled cputime accounting in 
dedicated functions.
This one is also pure code re-organisation, unless you've been able to 
spot a particular issue ?
Maybe commit cf9efce0ce31 ("powerpc: Account time using timebase rather 
than PURR")

It removed snapshot_timebases() and I can't see anything to replace it.
Yes. But this patch is dependent on Frederic's series.
backporting that is going to be difficult. So i am thinking to avoid putting Fixes tag.

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  arch/powerpc/kernel/time.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 3460d1a5a97c..11145c40183d 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -377,7 +377,6 @@ void vtime_task_switch(struct task_struct *prev)
      }
  }
-#ifdef CONFIG_NO_HZ_COMMON
  /**
   * vtime_reset - Fast forward vtime entry clocks
   *
@@ -394,6 +393,7 @@ void vtime_reset(void)
  #endif
  }
+#ifdef CONFIG_NO_HZ_COMMON
  /**
   * vtime_dyntick_start - Inform vtime about entry to idle-dynticks
   *
@@ -933,6 +933,7 @@ static void __init set_decrementer_max(void)
  static void __init init_decrementer_clockevent(void)
  {
      register_decrementer_clockevent(smp_processor_id());
+    vtime_reset();
  }
  void secondary_cpu_time_init(void)
@@ -948,6 +949,7 @@ void secondary_cpu_time_init(void)
      /* FIME: Should make unrelated change to move snapshot_timebase
       * call here ! */
      register_decrementer_clockevent(smp_processor_id());
+    vtime_reset();
  }
  /*
Sorry i should have put this earlier, But this applies on top of tip/timers/nohz
at 6199f9999a9b (origin/timers/nohz) sched/cputime: Handle dyntick-idle steal time correctly
(In case anyone tried applying on powerpc tree, it would fail)
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