From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Anton Blanchard <anton@ozlabs.org>,
"Oliver O'Halloran" <oohall@gmail.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Michael Neuling <mikey@neuling.org>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Jordan Niethe <jniethe5@gmail.com>,
Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
Subject: [PATCH v5 06/10] powerpc/smp: Optimize start_secondary
Date: Mon, 10 Aug 2020 12:48:30 +0530 [thread overview]
Message-ID: <20200810071834.92514-7-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200810071834.92514-1-srikar@linux.vnet.ibm.com>
In start_secondary, even if shared_cache was already set, system does a
redundant match for cpumask. This redundant check can be removed by
checking if shared_cache is already set.
While here, localize the sibling_mask variable to within the if
condition.
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v4 ->v5:
Retain cache domain, no need for generalization
(Michael Ellerman, Peter Zijlstra,
Valentin Schneider, Gautham R. Shenoy)
Changelog v1 -> v2:
Moved shared_cache topology fixup to fixup_topology (Gautham)
arch/powerpc/kernel/smp.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 0c960ce3be42..91cf5d05e7ec 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -851,7 +851,7 @@ static int powerpc_shared_cache_flags(void)
*/
static const struct cpumask *shared_cache_mask(int cpu)
{
- return cpu_l2_cache_mask(cpu);
+ return per_cpu(cpu_l2_cache_map, cpu);
}
#ifdef CONFIG_SCHED_SMT
@@ -1305,7 +1305,6 @@ static void add_cpu_to_masks(int cpu)
void start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
- struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
mmgrab(&init_mm);
current->active_mm = &init_mm;
@@ -1331,14 +1330,20 @@ void start_secondary(void *unused)
/* Update topology CPU masks */
add_cpu_to_masks(cpu);
- if (has_big_cores)
- sibling_mask = cpu_smallcore_mask;
/*
* Check for any shared caches. Note that this must be done on a
* per-core basis because one core in the pair might be disabled.
*/
- if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu)))
- shared_caches = true;
+ if (!shared_caches) {
+ struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
+ struct cpumask *mask = cpu_l2_cache_mask(cpu);
+
+ if (has_big_cores)
+ sibling_mask = cpu_smallcore_mask;
+
+ if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu)))
+ shared_caches = true;
+ }
set_numa_node(numa_cpu_lookup_table[cpu]);
set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
--
2.18.2
next prev parent reply other threads:[~2020-08-10 7:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-10 7:18 [PATCH v5 00/10] Coregroup support on Powerpc Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 01/10] powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 02/10] powerpc/smp: Merge Power9 topology with Power topology Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 03/10] powerpc/smp: Move powerpc_topology above Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 04/10] powerpc/smp: Move topology fixups into a new function Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling Srikar Dronamraju
2020-09-11 11:55 ` Michael Ellerman
2020-09-12 4:46 ` Srikar Dronamraju
2020-09-13 1:46 ` Michael Ellerman
2020-09-13 16:53 ` Srikar Dronamraju
2020-09-13 17:10 ` Srikar Dronamraju
2020-09-13 17:42 ` Satheesh Rajendran
2020-08-10 7:18 ` Srikar Dronamraju [this message]
2020-08-12 5:37 ` [PATCH v5 06/10] powerpc/smp: Optimize start_secondary Gautham R Shenoy
2020-08-10 7:18 ` [PATCH v5 07/10] powerpc/numa: Detect support for coregroup Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 08/10] powerpc/smp: Allocate cpumask only after searching thread group Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 09/10] powerpc/smp: Create coregroup domain Srikar Dronamraju
2020-08-10 7:18 ` [PATCH v5 10/10] powerpc/smp: Implement cpu_to_coregroup_id Srikar Dronamraju
2020-09-17 11:27 ` [PATCH v5 00/10] Coregroup support on Powerpc Michael Ellerman
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