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>,
Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>
Subject: [PATCH 4/7] powerpc/smp: Optimize remove_cpu_from_masks
Date: Mon, 27 Jul 2020 13:25:29 +0530 [thread overview]
Message-ID: <20200727075532.30058-5-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200727075532.30058-1-srikar@linux.vnet.ibm.com>
Currently while offlining a cpu, we iterate through all the cpus in the
DIE to clear sibling, l2_cache and smallcore maps. However if there are
more number of cores in a DIE, we end up spending more time iterating
through cpus which are completely unrelated.
Optimize this by only iterating through lesser but relevant cpumap.
If shared_cache is set, cpu_l2_cache_map should be relevant else
cpu_sibling_map would be relevant.
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: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
arch/powerpc/kernel/smp.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index d476098fc25c..cde157483abf 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1254,14 +1254,21 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
#ifdef CONFIG_HOTPLUG_CPU
static void remove_cpu_from_masks(int cpu)
{
+ struct cpumask *(*mask_fn)(int) = cpu_sibling_mask;
int i;
- for_each_cpu(i, cpu_cpu_mask(cpu)) {
+ if (shared_caches)
+ mask_fn = cpu_l2_cache_mask;
+
+ for_each_cpu(i, mask_fn(cpu)) {
set_cpus_unrelated(cpu, i, cpu_l2_cache_mask);
set_cpus_unrelated(cpu, i, cpu_sibling_mask);
if (has_big_cores)
set_cpus_unrelated(cpu, i, cpu_smallcore_mask);
- if (has_coregroup_support())
+ }
+
+ if (has_coregroup_support()) {
+ for_each_cpu(i, cpu_coregroup_mask(cpu))
set_cpus_unrelated(cpu, i, cpu_coregroup_mask);
}
}
--
2.17.1
next prev parent reply other threads:[~2020-07-27 7:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 7:55 [PATCH 0/7] Optimization to improve cpu online/offline on Powerpc Srikar Dronamraju
2020-07-27 7:55 ` [PATCH 1/7] powerpc/topology: Update topology_core_cpumask Srikar Dronamraju
2020-07-27 7:55 ` [PATCH 2/7] powerpc/smp: Stop updating cpu_core_mask Srikar Dronamraju
2020-07-27 7:55 ` [PATCH 3/7] powerpc/smp: Remove get_physical_package_id Srikar Dronamraju
2020-07-27 7:55 ` Srikar Dronamraju [this message]
2020-07-27 7:55 ` [PATCH 5/7] powerpc/smp: Limit cpus traversed to within a node Srikar Dronamraju
2020-07-27 7:55 ` [PATCH 6/7] powerpc/smp: Stop passing mask to update_mask_by_l2 Srikar Dronamraju
2020-07-27 7:55 ` [PATCH 7/7] powerpc/smp: Depend on cpu_l1_cache_map when adding cpus Srikar Dronamraju
2020-07-29 12:54 ` [PATCH 0/7] Optimization to improve cpu online/offline on Powerpc Satheesh Rajendran
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