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From: Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>,
	Suresh B Siddha <suresh.b.siddha@intel.com>,
	Ingo Molnar <mingo@elte.hu>,
	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: svaidy@linux.vnet.ibm.com,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	mahesh@linux.vnet.ibm.com
Subject: [PATCH][REPOST] Don't export sched_mc_power_savings on multi-socket single core system
Date: Mon, 11 May 2009 18:00:03 +0530	[thread overview]
Message-ID: <4A081A4B.1000204@linux.vnet.ibm.com> (raw)

My previous post got lost somewhere in lkml list. Hence reposting this 
patch again.

Fix to prevent sched_mc_power_saving from being exported through sysfs
for multi-scoket single core system. Max cores should be always greater than
one (1). My earlier patch that introduced fix for not exporting
'sched_mc_power_saving' on laptops  broke it on multi-socket single core
system. This fix addresses issue on both laptop and multi-socket single 
core system.
Below are the Test results:

1. Single socket - multi-core
       Before Patch: Does not export 'sched_mc_power_saving'
       After Patch: Does not export 'sched_mc_power_saving'
       Result: Pass

2. Multi Socket - single core
      Before Patch: exports 'sched_mc_power_saving'
      After Patch: Does not export 'sched_mc_power_saving'
      Result: Pass

3. Multi Socket - Multi core
      Before Patch: exports 'sched_mc_power_saving'
      After Patch: exports 'sched_mc_power_saving'


Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

Index: linux-2.6/arch/x86/include/asm/topology.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/topology.h
+++ linux-2.6/arch/x86/include/asm/topology.h
@@ -203,7 +203,8 @@ struct pci_bus;
  void x86_pci_root_bus_res_quirks(struct pci_bus *b);

  #ifdef CONFIG_SMP
-#define mc_capable()	(cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids)
+#define mc_capable()	(boot_cpu_data.x86_max_cores > 1) && \
+			(cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids)
  #define smt_capable()			(smp_num_siblings > 1)
  #endif

             reply	other threads:[~2009-05-11 12:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-11 12:30 Mahesh Jagannath Salgaonkar [this message]
2009-05-11 12:35 ` [PATCH][REPOST] Don't export sched_mc_power_savings on multi-socket single core system Ingo Molnar
2009-05-11 14:39   ` [PATCH][REPOST] Don't export sched_mc_power_savings onmulti-socket " Vaidyanathan Srinivasan
2009-05-11 15:09     ` [tip:sched/core] sched: Don't export sched_mc_power_savings on multi-socket " tip-bot for Vaidyanathan Srinivasan
2009-05-11 22:27     ` tip-bot for Vaidyanathan Srinivasan

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