On Thu, Sep 26, 2013 at 09:21:44AM +0800, Fengguang Wu wrote:
> Hi Eric,
>
> We are glad to find that your below commit brings large increase in
> lo netperf throughput:
>
> 35596b2796713c6a9dc0 734d2725db879f3f6fcd
> ------------------------ ------------------------
> 761.80 +534.6% 4834.60
> lkp-ib03/micro/netperf/120s-200%-UDP_STREAM
> 168.10 +1317.4% 2382.70
> lkp-nex04/micro/netperf/120s-200%-UDP_STREAM
> 169.60 +979.4% 1830.70
> lkp-nex05/micro/netperf/120s-200%-UDP_STREAM
> 2154.20 +135.7% 5077.50
> lkp-sb03/micro/netperf/120s-200%-UDP_STREAM
> 3559.00 -3.5% 3435.20
> lkp-t410/micro/netperf/120s-200%-TCP_STREAM
> 6812.70 +157.8% 17560.70 TOTAL
> netperf.Throughput_Mbps
>
> The side effects are some increased/decreased lock contentions:
This direct view may be more clear. Before patch:
class name con-bounces contentions
waittime-min waittime-max waittime-total acq-bounces acquis
itions holdtime-min holdtime-max holdtime-total
-------------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------
&(&nf->lru_lock)->rlock: 19017744 19034681
0.15 5884.35 5772892473.69 20428335 20
475976 0.10 1109.59 77448429.38
-----------------------
&(&nf->lru_lock)->rlock 4905538
[<ffffffff819227b9>] ip_defrag+0xa4f/0xbd3
&(&nf->lru_lock)->rlock 5695105
[<ffffffff8195bd6f>] inet_frag_find+0x2c7/0x30d
&(&nf->lru_lock)->rlock 5629414
[<ffffffff8195be74>] inet_frag_kill+0xbf/0x117
&(&nf->lru_lock)->rlock 2804624
[<ffffffff8195bf29>] inet_frag_evictor+0x5d/0x103
-----------------------
&(&nf->lru_lock)->rlock 6172104
[<ffffffff8195bd6f>] inet_frag_find+0x2c7/0x30d
&(&nf->lru_lock)->rlock 5348696
[<ffffffff8195be74>] inet_frag_kill+0xbf/0x117
&(&nf->lru_lock)->rlock 4421308
[<ffffffff819227b9>] ip_defrag+0xa4f/0xbd3
&(&nf->lru_lock)->rlock 3092573
[<ffffffff8195bf29>] inet_frag_evictor+0x5d/0x103
...............................................................................................................................................................................................
&(&q->lock)->rlock: 2322575 2323896
0.22 5802.58 934469091.38 3041941 13000848
0.10 5902.91 2811690638.18
------------------
&(&q->lock)->rlock 2163449
[<ffffffff8195bf7e>] inet_frag_evictor+0xb2/0x103
&(&q->lock)->rlock 160447
[<ffffffff81921e91>] ip_defrag+0x127/0xbd3
------------------
&(&q->lock)->rlock 2165896
[<ffffffff81921e91>] ip_defrag+0x127/0xbd3
&(&q->lock)->rlock 158000
[<ffffffff8195bf7e>] inet_frag_evictor+0xb2/0x103
...............................................................................................................................................................................................
&(&zone->lock)->rlock: 1845042 1851805
0.18 4917.52 19475590.18 9003807 10134386
0.13 3747.70 8347088.06
---------------------
&(&zone->lock)->rlock 866751
[<ffffffff8116fbbc>] __free_pages_ok.part.47+0x94/0x2a1
&(&zone->lock)->rlock 984597
[<ffffffff8116f856>] get_page_from_freelist+0x4a3/0x6e8
&(&zone->lock)->rlock 112
[<ffffffff8116fe3b>] free_pcppages_bulk+0x35/0x31a
&(&zone->lock)->rlock 116
[<ffffffff8116f72c>] get_page_from_freelist+0x379/0x6e8
---------------------
&(&zone->lock)->rlock 918190
[<ffffffff8116fbbc>] __free_pages_ok.part.47+0x94/0x2a1
&(&zone->lock)->rlock 722
[<ffffffff8116f72c>] get_page_from_freelist+0x379/0x6e8
&(&zone->lock)->rlock 861
[<ffffffff8116fe3b>] free_pcppages_bulk+0x35/0x31a
&(&zone->lock)->rlock 922607
[<ffffffff8116f856>] get_page_from_freelist+0x4a3/0x6e8
After patch, top contented locks become:
&(&zone->lock)->rlock: 58469530 58470181
0.16 4838.84 238618042.87 107374530 107408478
0.13 3610.05 73617127.93
---------------------
&(&zone->lock)->rlock 29783268
[<ffffffff8116f856>] get_page_from_freelist+0x4a3/0x6e8
&(&zone->lock)->rlock 837
[<ffffffff8116f72c>] get_page_from_freelist+0x379/0x6e8
&(&zone->lock)->rlock 1105
[<ffffffff8116fe3b>] free_pcppages_bulk+0x35/0x31a
&(&zone->lock)->rlock 28684627
[<ffffffff8116fbbc>] __free_pages_ok.part.47+0x94/0x2a1
---------------------
&(&zone->lock)->rlock 11356
[<ffffffff8116fe3b>] free_pcppages_bulk+0x35/0x31a
&(&zone->lock)->rlock 6741
[<ffffffff8116f72c>] get_page_from_freelist+0x379/0x6e8
&(&zone->lock)->rlock 28880589
[<ffffffff8116f856>] get_page_from_freelist+0x4a3/0x6e8
&(&zone->lock)->rlock 29558251
[<ffffffff8116fbbc>] __free_pages_ok.part.47+0x94/0x2a1
...............................................................................................................................................................................................
slock-AF_INET: 507780 508036
0.20 1167.78 2564695.48 11115246 106594271
0.12 1196.01 989718694.82
-------------
slock-AF_INET 434691
[<ffffffff818ed738>] lock_sock_fast+0x2f/0x84
slock-AF_INET 73294
[<ffffffff819482dc>] udp_queue_rcv_skb+0x1ba/0x3aa
slock-AF_INET 51
[<ffffffff818ed6b5>] lock_sock_nested+0x34/0x88
-------------
slock-AF_INET 434615
[<ffffffff819482dc>] udp_queue_rcv_skb+0x1ba/0x3aa
slock-AF_INET 73370
[<ffffffff818ed738>] lock_sock_fast+0x2f/0x84
slock-AF_INET 51
[<ffffffff8193fae1>] tcp_v4_rcv+0x390/0x978
..............................................................................................................................................................................................
&rq->lock: 286309 286456
0.21 294.85 1768779.90 5887506 244517912
0.09 1080.71 315600465.71
---------
&rq->lock 92057
[<ffffffff81a0aa65>] __schedule+0x103/0x852
&rq->lock 18386
[<ffffffff810ecc02>] try_to_wake_up+0x95/0x26c
&rq->lock 730
[<ffffffff810f13fb>] update_blocked_averages+0x30/0x47f
&rq->lock 304
[<ffffffff81a0af43>] __schedule+0x5e1/0x852
---------
&rq->lock 107807
[<ffffffff810ecd7b>] try_to_wake_up+0x20e/0x26c
&rq->lock 144391
[<ffffffff81a0aa65>] __schedule+0x103/0x852
&rq->lock 924
[<ffffffff810ecc02>] try_to_wake_up+0x95/0x26c
&rq->lock 29
[<ffffffff810e9090>] task_rq_lock+0x4b/0x85
Thanks,
Fengguang
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