From: Paul Mackerras <paulus@ozlabs.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, Jeremy Kerr <jk@ozlabs.org>,
Steven Rostedt <rostedt@goodmis.org>,
Nathan Fontenot <nfont@linux.vnet.ibm.com>
Subject: Re: [PATCH v1 3/5] powerpc/pseries: Fix stolen time accounting when dtl debugfs is used
Date: Fri, 26 Oct 2018 08:08:07 +1100 [thread overview]
Message-ID: <20181025210807.GA23232@blackberry> (raw)
In-Reply-To: <16929569199445cd09d9142505b2349620328b38.1540488386.git.naveen.n.rao@linux.vnet.ibm.com>
On Fri, Oct 26, 2018 at 01:55:44AM +0530, Naveen N. Rao wrote:
> When the dtl debugfs interface is used, we usually set the
> dtl_enable_mask to 0x7 (DTL_LOG_ALL). When this happens, we start seeing
> DTL entries for all preempt reasons, including CEDE. In
> scan_dispatch_log(), we add up the times from all entries and account
> those towards stolen time. However, we should only be accounting stolen
> time when the preemption was due to HDEC at the end of our time slice.
It's always been the case that stolen time when idle has been
accounted as idle time, not stolen time. That's why we didn't check
for this in the past.
Do you have a test that shows different results (as in reported idle
and stolen times) with this patch compared to without?
Paul.
next prev parent reply other threads:[~2018-10-25 22:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 20:25 [PATCH v1 0/5] Add dtl_entry tracepoint Naveen N. Rao
2018-10-25 20:25 ` [PATCH v1 1/5] powerpc/pseries: Use macros for referring to the DTL enable mask Naveen N. Rao
2018-10-25 20:25 ` [PATCH v1 2/5] powerpc/pseries: Do not save the previous DTL mask value Naveen N. Rao
2018-10-25 20:25 ` [PATCH v1 3/5] powerpc/pseries: Fix stolen time accounting when dtl debugfs is used Naveen N. Rao
2018-10-25 21:08 ` Paul Mackerras [this message]
2018-10-26 7:40 ` Naveen N. Rao
2018-10-25 20:25 ` [PATCH v1 4/5] powerpc/pseries: Factor out DTL buffer allocation and registration routines Naveen N. Rao
2018-10-25 20:25 ` [PATCH v1 5/5] powerpc/pseries: Introduce dtl_entry tracepoint Naveen N. Rao
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