From: "Huang\, Ying" <ying.huang@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@redhat.com>,
Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [RFC 08/10] autonuma, memory tiering: Select hotter pages to promote to fast memory node
Date: Mon, 04 Nov 2019 18:13:21 +0800 [thread overview]
Message-ID: <87bltsar0e.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <20191104084404.GA4131@hirez.programming.kicks-ass.net> (Peter Zijlstra's message of "Mon, 4 Nov 2019 09:44:04 +0100")
Peter Zijlstra <peterz@infradead.org> writes:
> On Mon, Nov 04, 2019 at 10:41:10AM +0800, Huang, Ying wrote:
>
>> >> +#define NUMA_SCAN_NR_HIST 16
>> >> + int numa_scan_idx;
>> >> + unsigned long numa_scan_jiffies[NUMA_SCAN_NR_HIST];
>> >> + unsigned long numa_scan_starts[NUMA_SCAN_NR_HIST];
>> >
>> > Why 16? This is 4 cachelines.
>>
>> We want to keep the NUMA scanning history reasonably long. From
>> task_scan_min(), the minimal interval between task_numa_work() running
>> is about 100 ms by default. So we can keep 1600 ms history by default
>> if NUMA_SCAN_NR_HIST is 16. If user choose to use smaller
>> sysctl_numa_balancing_scan_size, then we can only keep shorter history.
>> In general, we want to keep no less than 1000 ms history. So 16 appears
>> like a reasonable choice for us. Any other suggestion?
>
> This is very good information for Changelogs and comments :-)
Thanks! Will do this in the next version.
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2019-11-04 10:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 7:57 [RFC 00/10] autonuma: Optimize memory placement in memory tiering system Huang, Ying
2019-11-01 7:57 ` [RFC 01/10] autonuma: Fix watermark checking in migrate_balanced_pgdat() Huang, Ying
2019-11-01 11:11 ` Mel Gorman
2019-11-01 7:57 ` [RFC 02/10] autonuma: Reduce cache footprint when scanning page tables Huang, Ying
2019-11-01 11:13 ` Mel Gorman
2019-11-01 7:57 ` [RFC 03/10] autonuma: Add NUMA_BALANCING_MEMORY_TIERING mode Huang, Ying
2019-11-01 7:57 ` [RFC 04/10] autonuma, memory tiering: Rate limit NUMA migration throughput Huang, Ying
2019-11-01 7:57 ` [RFC 05/10] autonuma, memory tiering: Use kswapd to demote cold pages to PMEM Huang, Ying
2019-11-01 7:57 ` [RFC 06/10] autonuma, memory tiering: Skip to scan fastest memory Huang, Ying
2019-11-01 7:57 ` [RFC 07/10] autonuma, memory tiering: Only promote page if accessed twice Huang, Ying
2019-11-01 7:57 ` [RFC 08/10] autonuma, memory tiering: Select hotter pages to promote to fast memory node Huang, Ying
2019-11-01 9:24 ` Peter Zijlstra
2019-11-04 2:41 ` Huang, Ying
2019-11-04 8:44 ` Peter Zijlstra
2019-11-04 10:13 ` Huang, Ying [this message]
2019-11-01 7:57 ` [RFC 09/10] autonuma, memory tiering: Double hot threshold for write hint page fault Huang, Ying
2019-11-01 7:57 ` [RFC 10/10] autonuma, memory tiering: Adjust hot threshold automatically Huang, Ying
2019-11-01 9:31 ` Peter Zijlstra
2019-11-04 6:11 ` Huang, Ying
2019-11-04 8:49 ` Peter Zijlstra
2019-11-04 10:12 ` Huang, Ying
2019-11-21 8:38 ` Huang, Ying
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