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Message-ID: <20231019033323.54147-1-yangyicong@huawei.com>
Date: Thu, 19 Oct 2023 11:33:20 +0800
From: Yicong Yang <yangyicong@...wei.com>
To: <peterz@...radead.org>, <mingo@...hat.com>,
<juri.lelli@...hat.com>, <vincent.guittot@...aro.org>,
<dietmar.eggemann@....com>, <tim.c.chen@...ux.intel.com>,
<yu.c.chen@...el.com>, <gautham.shenoy@....com>, <mgorman@...e.de>,
<vschneid@...hat.com>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
CC: <rostedt@...dmis.org>, <bsegall@...gle.com>, <bristot@...hat.com>,
<prime.zeng@...wei.com>, <yangyicong@...ilicon.com>,
<jonathan.cameron@...wei.com>, <ego@...ux.vnet.ibm.com>,
<srikar@...ux.vnet.ibm.com>, <linuxarm@...wei.com>,
<21cnbao@...il.com>, <kprateek.nayak@....com>,
<wuyun.abel@...edance.com>
Subject: [PATCH v11 0/3] sched/fair: Scan cluster before scanning LLC in wake-up path
From: Yicong Yang <yangyicong@...ilicon.com>
This is the follow-up work to support cluster scheduler. Previously
we have added cluster level in the scheduler for both ARM64[1] and
X86[2] to support load balance between clusters to bring more memory
bandwidth and decrease cache contention. This patchset, on the other
hand, takes care of wake-up path by giving CPUs within the same cluster
a try before scanning the whole LLC to benefit those tasks communicating
with each other.
[1] 778c558f49a2 ("sched: Add cluster scheduler level in core and related Kconfig for ARM64")
[2] 66558b730f25 ("sched: Add cluster scheduler level for x86")
Change since v10:
- Add tags from Vincent and Gautham for Patch 2/3, thanks!
- Remove redundant idle check for prev/recent_used cpu in Patch 3/3.
Link: https://lore.kernel.org/all/20231012121707.51368-1-yangyicong@huawei.com/
Change since v9:
- Since EEVDF merged in mainline, rebase and test on tip-sched-core
- Split a Patch 3/3 to solve the hackbench regression on Jacobsville, for easier review
Link: https://lore.kernel.org/lkml/20230719092838.2302-1-yangyicong@huawei.com/
Change since v8:
- Peter find cpus_share_lowest_cache() is weired so fallback to cpus_share_resources()
suggested in v4
- Use sd->groups->flags to find the cluster when scanning, save one per-cpu pointer
- Fix sched_cluster_active enabled incorrectly on domain degeneration
- Use sched_cluster_active to avoid repeated check on non-cluster machines, per Gautham
Link: https://lore.kernel.org/all/20230530070253.33306-1-yangyicong@huawei.com/
Change since v7:
- Optimize by choosing prev_cpu/recent_used_cpu when possible after failed to
scanning for an idle CPU in cluster/LLC. Thanks Chen Yu for testing on Jacobsville
Link: https://lore.kernel.org/all/20220915073423.25535-1-yangyicong@huawei.com/
Change for RESEND:
- Collect tag from Chen Yu and rebase on the latest tip/sched/core. Thanks.
Link: https://lore.kernel.org/lkml/20220822073610.27205-1-yangyicong@huawei.com/
Change since v6:
- rebase on 6.0-rc1
Link: https://lore.kernel.org/lkml/20220726074758.46686-1-yangyicong@huawei.com/
Change since v5:
- Improve patch 2 according to Peter's suggestion:
- use sched_cluster_active to indicate whether cluster is active
- consider SMT case and use wrap iteration when scanning cluster
- Add Vincent's tag
Thanks.
Link: https://lore.kernel.org/lkml/20220720081150.22167-1-yangyicong@hisilicon.com/
Change since v4:
- rename cpus_share_resources to cpus_share_lowest_cache to be more informative, per Tim
- return -1 when nr==0 in scan_cluster(), per Abel
Thanks!
Link: https://lore.kernel.org/lkml/20220609120622.47724-1-yangyicong@hisilicon.com/
Change since v3:
- fix compile error when !CONFIG_SCHED_CLUSTER, reported by lkp test.
Link: https://lore.kernel.org/lkml/20220608095758.60504-1-yangyicong@hisilicon.com/
Change since v2:
- leverage SIS_PROP to suspend redundant scanning when LLC is overloaded
- remove the ping-pong suppression
- address the comment from Tim, thanks.
Link: https://lore.kernel.org/lkml/20220126080947.4529-1-yangyicong@hisilicon.com/
Change since v1:
- regain the performance data based on v5.17-rc1
- rename cpus_share_cluster to cpus_share_resources per Vincent and Gautham, thanks!
Link: https://lore.kernel.org/lkml/20211215041149.73171-1-yangyicong@hisilicon.com/
Barry Song (2):
sched: Add cpus_share_resources API
sched/fair: Scan cluster before scanning LLC in wake-up path
Yicong Yang (1):
sched/fair: Use candidate prev/recent_used CPU if scanning failed for
cluster wakeup
include/linux/sched/sd_flags.h | 7 ++++
include/linux/sched/topology.h | 8 ++++-
kernel/sched/core.c | 12 +++++++
kernel/sched/fair.c | 58 +++++++++++++++++++++++++++++++---
kernel/sched/sched.h | 2 ++
kernel/sched/topology.c | 25 +++++++++++++++
6 files changed, 106 insertions(+), 6 deletions(-)
--
2.24.0
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