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From: Aaron Lu <aaron.lu@intel.com>
To: David Vernet <void@manifault.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	<linux-kernel@vger.kernel.org>, <mingo@redhat.com>,
	<juri.lelli@redhat.com>, <vincent.guittot@linaro.org>,
	<rostedt@goodmis.org>, <dietmar.eggemann@arm.com>,
	<bsegall@google.com>, <mgorman@suse.de>, <bristot@redhat.com>,
	<vschneid@redhat.com>, <joshdon@google.com>,
	<roman.gushchin@linux.dev>, <tj@kernel.org>,
	<kernel-team@meta.com>
Subject: Re: [RFC PATCH 3/3] sched: Implement shared wakequeue in CFS
Date: Thu, 15 Jun 2023 15:31:53 +0800	[thread overview]
Message-ID: <20230615073153.GA110814@ziqianlu-dell> (raw)
In-Reply-To: <20230615044917.GA109334@ziqianlu-dell>

On Thu, Jun 15, 2023 at 12:49:17PM +0800, Aaron Lu wrote:
> I'll see if I can find a smaller machine and give it a run there too.

Found a Skylake with 18cores/36threads on each socket/LLC and with
netperf, the contention is still serious.

"
$ netserver
$ sudo sh -c "echo SWQUEUE > /sys/kernel/debug/sched/features"
$ for i in `seq 72`; do netperf -l 60 -n 72 -6 -t UDP_RR & done
"

        53.61%    53.61%  [kernel.vmlinux]            [k] native_queued_spin_lock_slowpath            -      -            
            |          
            |--27.93%--sendto
            |          entry_SYSCALL_64
            |          do_syscall_64
            |          |          
            |           --27.93%--__x64_sys_sendto
            |                     __sys_sendto
            |                     sock_sendmsg
            |                     inet6_sendmsg
            |                     udpv6_sendmsg
            |                     udp_v6_send_skb
            |                     ip6_send_skb
            |                     ip6_local_out
            |                     ip6_output
            |                     ip6_finish_output
            |                     ip6_finish_output2
            |                     __dev_queue_xmit
            |                     __local_bh_enable_ip
            |                     do_softirq.part.0
            |                     __do_softirq
            |                     net_rx_action
            |                     __napi_poll
            |                     process_backlog
            |                     __netif_receive_skb
            |                     __netif_receive_skb_one_core
            |                     ipv6_rcv
            |                     ip6_input
            |                     ip6_input_finish
            |                     ip6_protocol_deliver_rcu
            |                     udpv6_rcv
            |                     __udp6_lib_rcv
            |                     udp6_unicast_rcv_skb
            |                     udpv6_queue_rcv_skb
            |                     udpv6_queue_rcv_one_skb
            |                     __udp_enqueue_schedule_skb
            |                     sock_def_readable
            |                     __wake_up_sync_key
            |                     __wake_up_common_lock
            |                     |          
            |                      --27.85%--__wake_up_common
            |                                receiver_wake_function
            |                                autoremove_wake_function
            |                                default_wake_function
            |                                try_to_wake_up
            |                                |          
            |                                 --27.85%--ttwu_do_activate
            |                                           enqueue_task
            |                                           enqueue_task_fair
            |                                           |          
            |                                            --27.85%--_raw_spin_lock_irqsave
            |                                                      |          
            |                                                       --27.85%--native_queued_spin_lock_slowpath
            |          
             --25.67%--recvfrom
                       entry_SYSCALL_64
                       do_syscall_64
                       __x64_sys_recvfrom
                       __sys_recvfrom
                       sock_recvmsg
                       inet6_recvmsg
                       udpv6_recvmsg
                       __skb_recv_udp
                       |          
                        --25.67%--__skb_wait_for_more_packets
                                  schedule_timeout
                                  schedule
                                  __schedule
                                  |          
                                   --25.66%--pick_next_task_fair
                                             |          
                                              --25.65%--swqueue_remove_task
                                                        |          
                                                         --25.65%--_raw_spin_lock_irqsave
                                                                   |          
                                                                    --25.65%--native_queued_spin_lock_slowpath

I didn't aggregate the throughput(Trans. Rate per sec) from all these
clients, but a glimpse from the result showed that the throughput of
each client dropped from 4xxxx(NO_SWQUEUE) to 2xxxx(SWQUEUE).

Thanks,
Aaron

  reply	other threads:[~2023-06-15  7:33 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-13  5:20 [RFC PATCH 0/3] sched: Implement shared wakequeue in CFS David Vernet
2023-06-13  5:20 ` [RFC PATCH 1/3] sched: Make migrate_task_to() take any task David Vernet
2023-06-21 13:04   ` Peter Zijlstra
2023-06-22  2:07     ` David Vernet
2023-06-13  5:20 ` [RFC PATCH 2/3] sched/fair: Add SWQUEUE sched feature and skeleton calls David Vernet
2023-06-21 12:49   ` Peter Zijlstra
2023-06-22 14:53     ` David Vernet
2023-06-13  5:20 ` [RFC PATCH 3/3] sched: Implement shared wakequeue in CFS David Vernet
2023-06-13  8:32   ` Peter Zijlstra
2023-06-14  4:35     ` Aaron Lu
2023-06-14  9:27       ` Peter Zijlstra
2023-06-15  0:01       ` David Vernet
2023-06-15  4:49         ` Aaron Lu
2023-06-15  7:31           ` Aaron Lu [this message]
2023-06-15 23:26             ` David Vernet
2023-06-16  0:53               ` Aaron Lu
2023-06-20 17:36                 ` David Vernet
2023-06-21  2:35                   ` Aaron Lu
2023-06-21  2:43                     ` David Vernet
2023-06-21  4:54                       ` Aaron Lu
2023-06-21  5:43                         ` David Vernet
2023-06-21  6:03                           ` Aaron Lu
2023-06-22 15:57                             ` Chris Mason
2023-06-13  8:41   ` Peter Zijlstra
2023-06-14 20:26     ` David Vernet
2023-06-16  8:08   ` Vincent Guittot
2023-06-20 19:54     ` David Vernet
2023-06-20 21:37       ` Roman Gushchin
2023-06-21 14:22       ` Peter Zijlstra
2023-06-19  6:13   ` Gautham R. Shenoy
2023-06-20 20:08     ` David Vernet
2023-06-21  8:17       ` Gautham R. Shenoy
2023-06-22  1:43         ` David Vernet
2023-06-22  9:11           ` Gautham R. Shenoy
2023-06-22 10:29             ` Peter Zijlstra
2023-06-23  9:50               ` Gautham R. Shenoy
2023-06-26  6:04                 ` Gautham R. Shenoy
2023-06-27  3:17                   ` David Vernet
2023-06-27 16:31                     ` Chris Mason
2023-06-21 14:20   ` Peter Zijlstra
2023-06-21 20:34     ` David Vernet
2023-06-22 10:58       ` Peter Zijlstra
2023-06-22 14:43         ` David Vernet
2023-07-10 11:57 ` [RFC PATCH 0/3] " K Prateek Nayak
2023-07-11  4:43   ` David Vernet
2023-07-11  5:06     ` K Prateek Nayak

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