From: Peter Zijlstra <peterz@infradead.org>
To: Jirka Hladky <jhladky@redhat.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Kamil Kolakowski <kkolakow@redhat.com>
Subject: Re: Kernel 4.7rc3 - Performance drop 30-40% for SPECjbb2005 and SPECjvm2008 benchmarks against 4.6 kernel
Date: Wed, 22 Jun 2016 22:59:11 +0200 [thread overview]
Message-ID: <20160622205911.GW30909@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAE4VaGB05Yyx+u0v6r75D1hPJzTJkBrKU-k9MDHTPCkE=SH-nQ@mail.gmail.com>
On Wed, Jun 22, 2016 at 04:41:06PM +0200, Jirka Hladky wrote:
> This commit is bad:
> 2159197 - Peter Zijlstra, 8 weeks ago : sched/core: Enable increased
> load resolution on 64-bit kernels
>
> Could you please have a look?
Yes, that is indeed the culprit.
The below 'revert' makes it go fast again. I'll try and figure out
what's wrong tomorrow.
---
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index bf6fea9..e7e312b 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -55,7 +55,7 @@ static inline void cpu_load_update_active(struct rq *this_rq) { }
* Really only required when CONFIG_FAIR_GROUP_SCHED is also set, but to
* increase coverage and consistency always enable it on 64bit platforms.
*/
-#ifdef CONFIG_64BIT
+#if 0 // def CONFIG_64BIT
# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w) ((w) << SCHED_FIXEDPOINT_SHIFT)
# define scale_load_down(w) ((w) >> SCHED_FIXEDPOINT_SHIFT)
next prev parent reply other threads:[~2016-06-22 20:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 16:38 Jirka Hladky
2016-06-16 17:22 ` Peter Zijlstra
2016-06-16 23:04 ` Jirka Hladky
2016-06-21 13:17 ` Jirka Hladky
2016-06-22 7:16 ` Peter Zijlstra
2016-06-22 7:49 ` Peter Zijlstra
2016-06-22 7:54 ` Peter Zijlstra
2016-06-22 9:52 ` Jirka Hladky
2016-06-22 11:12 ` Peter Zijlstra
2016-06-22 12:37 ` Jirka Hladky
2016-06-22 12:46 ` Jirka Hladky
2016-06-22 14:41 ` Jirka Hladky
2016-06-22 20:59 ` Peter Zijlstra [this message]
2016-06-22 8:20 ` Jirka Hladky
2016-06-23 18:33 ` Peter Zijlstra
2016-06-23 18:43 ` Peter Zijlstra
2016-06-24 7:44 ` Jirka Hladky
2016-06-24 8:08 ` Peter Zijlstra
2016-06-24 8:20 ` Jirka Hladky
2016-06-24 12:02 ` Peter Zijlstra
2016-06-24 12:09 ` Jirka Hladky
2016-06-24 12:30 ` Peter Zijlstra
2016-06-24 12:35 ` Jirka Hladky
2016-06-24 12:44 ` Vincent Guittot
2016-06-24 13:08 ` Jirka Hladky
2016-06-24 13:09 ` Peter Zijlstra
2016-06-24 13:23 ` Vincent Guittot
2016-06-24 13:33 ` Peter Zijlstra
2016-06-24 13:45 ` Peter Zijlstra
2016-06-24 13:42 ` Peter Zijlstra
2016-06-24 15:54 ` Peter Zijlstra
2016-06-24 22:13 ` Jirka Hladky
2016-06-22 7:37 Branimir Maksimovic
2016-06-22 8:25 ` Jirka Hladky
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