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From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	WANG Xuerui <kernel@xen0n.name>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <chleroy@kernel.org>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Chen Yu <yu.c.chen@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>, <linux-kernel@vger.kernel.org>,
	<linux-arch@vger.kernel.org>, <linux-s390@vger.kernel.org>,
	<linuxppc-dev@lists.ozlabs.org>, <linux-mips@vger.kernel.org>,
	<loongarch@lists.linux.dev>, <driver-core@lists.linux.dev>,
	Sudeep Holla <sudeep.holla@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Danilo Krummrich <dakr@kernel.org>,
	Huacai Chen <chenhuacai@kernel.org>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Madhavan Srinivasan <maddy@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	"David S. Miller" <davem@davemloft.net>,
	Andreas Larsson <andreas@gaisler.com>,
	Thomas Gleixner <tglx@kernel.org>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>
Subject: Re: [RFC PATCH v3 01/13] lib/sbm: Introduce helpers for architectures to configure LLC properties
Date: Mon, 12 Oct 2026 07:41:38 +0530	[thread overview]
Message-ID: <a92f172e-7a3d-4fe5-94ae-b6768581a5c0@amd.com> (raw)
In-Reply-To: <bebd59dc-9932-41fe-9fa6-4d2cc8d15080@linux.ibm.com>

Hello Shrikanth,

On 10/7/2026 11:13 AM, Shrikanth Hegde wrote:
> Hi Prateek.
> 
> I ran the series on 320 CPU power11 system today.
> hackbench shows high regression across the different number of groups and
> it is more severe at lower number of groups. I haven't run anything else yet.
> 
> I haven't taken a look at the patches yet. Post your talk today will try to
> go through and see if i can spot something.

Thanks a ton for the testing. Now that I'm back, I'll take a look at
few bits again, especially stuff for optimizing traversals. 

Can you please share what does your system topology look like and what
did:

  sudo dmesg | grep sbm

say when you booted into your kernel?

>> +void __init sbm_set_topology(int num_instances, int max_threads_per_instance)
>> +{
>> +    sbm_max_threads_per_instance = max_threads_per_instance;
>> +    sbm_num_instance = num_instances;
>> +
>> +    pr_info("sbm topology set to %d instance(s) with a maximum of %d thread(s) per instance\n",
>> +        sbm_num_instance,
>> +        sbm_max_threads_per_instance);
>> +}
> 
> nit: Stray empty line at the end.

Ack! Thank you again for taking a look.

> 
>> +

-- 
Thanks and Regards,
Prateek


  reply	other threads:[~2026-10-12  2:12 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-01 19:28 [RFC PATCH v3 00/13] lib, sched: Introduce sparsebitmap (sbm) K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 01/13] lib/sbm: Introduce helpers for architectures to configure LLC properties K Prateek Nayak
2026-10-07  5:43   ` Shrikanth Hegde
2026-10-12  2:11     ` K Prateek Nayak [this message]
2026-10-01 19:28 ` [RFC PATCH v3 02/13] drivers/base/arch_topology: Add support for initializing sbm topology K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 03/13] LoongArch: Initialize CPU _PXM relation for disabled CPUs from SRAT K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 04/13] LoongArch: Configure sbm topology during SMP preparation K Prateek Nayak
2026-10-07  3:51   ` [RFC PATCH v3.1 " K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 05/13] MIPS: Initialize sbm topology on multi-node systems K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 06/13] powerpc/setup: Initialize sbm topology based on coregroup / NUMA topology K Prateek Nayak
2026-10-07 14:43   ` Shrikanth Hegde
2026-10-12  2:29     ` K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 07/13] s390/topology: Initialize sbm topology during topology_init_early() K Prateek Nayak
2026-10-07 10:19   ` Mete Durlu
2026-10-12  2:20     ` K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 08/13] sparc64: Initialize sbm topology on multi-LLC system K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 09/13] x86/cpu/topology: Initialize sbm topology after topology parsing K Prateek Nayak
2026-10-03  8:27   ` Chen Yu
2026-10-04  6:17     ` K Prateek Nayak
2026-10-07  3:52   ` [RFC PATCH v3.1 " K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 10/13] lib/sbm: Dynamically allocate sbm index when CPU is activated K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 11/13] lib/sbm: Add helpers to allocate, set, clear, and traverse the bits on sbm K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 12/13] sched/fair: Allocate nohz.idle_cpus_mask during sched_init_smp() K Prateek Nayak
2026-10-01 19:28 ` [RFC PATCH v3 13/13] sched/fair: Switch nohz.idle_cpus to use sbm K Prateek Nayak
2026-10-03  9:10 ` [RFC PATCH v3 00/13] lib, sched: Introduce sparsebitmap (sbm) Chen Yu
2026-10-04  6:13   ` K Prateek Nayak

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