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From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Tony Luck <tony.luck@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Stanislaw Gruszka <sgruszka@redhat.com>,
	Wanpeng Li <wanpeng.li@hotmail.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: [PATCH 02/10] ia64: Fix wrong start cputime assignment on task switch
Date: Thu,  5 Jan 2017 18:11:42 +0100	[thread overview]
Message-ID: <1483636310-6557-3-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1483636310-6557-1-git-send-email-fweisbec@gmail.com>

On task switch we must initialize the current cputime of the next task
using the value of the previous task which got freshly updated.

But we are confusing that with doing the opposite, which should result
in wrong cputime accounting.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 arch/ia64/kernel/time.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 71775b95..637e741 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -83,7 +83,7 @@ void arch_vtime_task_switch(struct task_struct *prev)
 	struct thread_info *pi = task_thread_info(prev);
 	struct thread_info *ni = task_thread_info(current);
 
-	pi->ac_stamp = ni->ac_stamp;
+	ni->ac_stamp = pi->ac_stamp;
 	ni->ac_stime = ni->ac_utime = 0;
 }
 
-- 
2.7.4

  parent reply	other threads:[~2017-01-05 17:13 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-05 17:11 [PATCH 00/10] vtime: Delay cputime accounting to tick / context switch Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 01/10] powerpc32: Fix stale scaled stime on " Frederic Weisbecker
2017-01-14 10:00   ` [tip:sched/core] sched/cputime, " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` Frederic Weisbecker [this message]
2017-01-14 10:00   ` [tip:sched/core] sched/cputime, ia64: Fix incorrect start cputime assignment on task switch tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 03/10] cputime: Allow accounting system time using cpustat index Frederic Weisbecker
2017-01-14 10:01   ` [tip:sched/core] sched/cputime: " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 04/10] cputime: Export account_guest_time Frederic Weisbecker
2017-01-14 10:01   ` [tip:sched/core] sched/cputime: Export account_guest_time() tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 05/10] powerpc: Prepare accounting structure for cputime flush on tick Frederic Weisbecker
2017-01-14 10:02   ` [tip:sched/core] sched/cputime, " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 06/10] powerpc: Migrate stolen_time field to accounting structure Frederic Weisbecker
2017-01-14 10:03   ` [tip:sched/core] sched/cputime, powerpc: Migrate stolen_time field to the " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 07/10] powerpc/vtime: Accumulate cputime and account only on tick/task switch Frederic Weisbecker
2017-01-14 10:03   ` [tip:sched/core] sched/cputime, " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 08/10] ia64: " Frederic Weisbecker
2017-01-14 10:04   ` [tip:sched/core] sched/cputime, " tip-bot for Frederic Weisbecker
2017-01-05 17:11 ` [PATCH 09/10] s390/cputime: delayed accounting of system time Frederic Weisbecker
2017-01-14 10:04   ` [tip:sched/core] sched/cputime, s390: Implement " tip-bot for Martin Schwidefsky
2017-01-05 17:11 ` [PATCH 10/10] vtime: Rename vtime_account_user() to vtime_flush() Frederic Weisbecker
2017-01-14 10:05   ` [tip:sched/core] sched/cputime: " tip-bot for Frederic Weisbecker
2017-01-09  8:13 ` [PATCH 00/10] vtime: Delay cputime accounting to tick / context switch Martin Schwidefsky
2017-01-10 11:45 ` Thomas Gleixner
2017-01-10 15:21   ` Frederic Weisbecker

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