Re: [RFC 0/3] reduce latency of direct async compaction

[Aaron Lu]

On 12/04/2015 08:38 PM, Vlastimil Babka wrote:
> On 12/04/2015 07:25 AM, Aaron Lu wrote:
>> On Thu, Dec 03, 2015 at 09:10:44AM +0100, Vlastimil Babka wrote:
>>> Aaron, could you try this on your testcase?
>>
>> One time result isn't stable enough, so I did 9 runs for each commit,
>> here is the result:
>>
>> base: 25364a9e54fb8296837061bf684b76d20eec01fb
>> head: 7433b1009ff5a02e1e9f3444802daba2cf385d27
>> (head =  base + this_patch_serie)
>>
>> The always-always case(transparent_hugepage set to always and defrag set
>> to always):
>>
>> Result for base:
>> $ cat {0..8}/swap
>> cmdline: /lkp/aaron/src/bin/usemem 100000622592
>> 100000622592 transferred in 103 seconds, throughput: 925 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99999559680
>> 99999559680 transferred in 92 seconds, throughput: 1036 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99996171264
>> 99996171264 transferred in 92 seconds, throughput: 1036 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100005663744
>> 100005663744 transferred in 150 seconds, throughput: 635 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100002966528
>> 100002966528 transferred in 87 seconds, throughput: 1096 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99995784192
>> 99995784192 transferred in 131 seconds, throughput: 727 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100003731456
>> 100003731456 transferred in 97 seconds, throughput: 983 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100006440960
>> 100006440960 transferred in 109 seconds, throughput: 874 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99998813184
>> 99998813184 transferred in 122 seconds, throughput: 781 MB/s
>> Max: 1096 MB/s
>> Min: 635 MB/s
>> Avg: 899 MB/s
>>
>> Result for head:
>> $ cat {0..8}/swap
>> cmdline: /lkp/aaron/src/bin/usemem 100003163136
>> 100003163136 transferred in 105 seconds, throughput: 908 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99998524416
>> 99998524416 transferred in 78 seconds, throughput: 1222 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99993646080
>> 99993646080 transferred in 108 seconds, throughput: 882 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99998936064
>> 99998936064 transferred in 114 seconds, throughput: 836 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100002204672
>> 100002204672 transferred in 73 seconds, throughput: 1306 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99998140416
>> 99998140416 transferred in 146 seconds, throughput: 653 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100002941952
>> 100002941952 transferred in 78 seconds, throughput: 1222 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99996917760
>> 99996917760 transferred in 109 seconds, throughput: 874 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100001405952
>> 100001405952 transferred in 96 seconds, throughput: 993 MB/s
>> Max: 1306 MB/s
>> Min: 653 MB/s
>> Avg: 988 MB/s
> 
> Ok that looks better than the first results :) The series either helped, 
> or it's just noise. But hopefully not worse.

Well, it looks to be the case :-)

> 
>> Result for v4.3 as a reference:
>> $ cat {0..8}/swap
>> cmdline: /lkp/aaron/src/bin/usemem 100002459648
>> 100002459648 transferred in 96 seconds, throughput: 993 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99997375488
>> 99997375488 transferred in 96 seconds, throughput: 993 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99999028224
>> 99999028224 transferred in 107 seconds, throughput: 891 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100000137216
>> 100000137216 transferred in 91 seconds, throughput: 1047 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100003835904
>> 100003835904 transferred in 80 seconds, throughput: 1192 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100000143360
>> 100000143360 transferred in 96 seconds, throughput: 993 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100020593664
>> 100020593664 transferred in 101 seconds, throughput: 944 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100005805056
>> 100005805056 transferred in 87 seconds, throughput: 1096 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100008360960
>> 100008360960 transferred in 74 seconds, throughput: 1288 MB/s
>> Max: 1288 MB/s
>> Min: 891 MB/s
>> Avg: 1048 MB/s
> 
> Hard to say if there's actual regression from 4.3 to 4.4, it's too 
> noisy. More iterations could help, but then the eventual bisection would 
> need them too.

One thing puzzles me most is that once compaction is involved, the
results will become undetermined, i.e. the result could be as high
as 1xxx MB/s or as low as 6xx MB/s. The always-never's case is much
better in this regard.

Thanks,
Aaron

> 
>> The always-never case:
>>
>> Result for head:
>> $ cat {0..8}/swap
>> cmdline: /lkp/aaron/src/bin/usemem 100003940352
>> 100003940352 transferred in 71 seconds, throughput: 1343 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100007411712
>> 100007411712 transferred in 62 seconds, throughput: 1538 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100001875968
>> 100001875968 transferred in 64 seconds, throughput: 1490 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100003912704
>> 100003912704 transferred in 62 seconds, throughput: 1538 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100002238464
>> 100002238464 transferred in 66 seconds, throughput: 1444 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100003670016
>> 100003670016 transferred in 65 seconds, throughput: 1467 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 99998364672
>> 99998364672 transferred in 68 seconds, throughput: 1402 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100005417984
>> 100005417984 transferred in 70 seconds, throughput: 1362 MB/s
>> cmdline: /lkp/aaron/src/bin/usemem 100005304320
>> 100005304320 transferred in 64 seconds, throughput: 1490 MB/s
>> Max: 1538 MB/s
>> Min: 1343 MB/s
>> Avg: 1452 MB/s
>>
> 

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