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Date: Wed, 26 Apr 2017 13:02:43 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: js1304@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Minchan Kim <minchan@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        linux-kernel@vger.kernel.org, kernel-team@lge.com,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH v4 2/4] zram: implement deduplication in zram
Message-ID: <20170426040243.GC673@jagdpanzerIV.localdomain>
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On (04/26/17 09:52), js1304@gmail.com wrote:
[..]
> <no-dedup>
> Elapsed time: out/host: 88 s
> mm_stat: 8834420736 3658184579 3834208256 0 3834208256 32889 0 0 0
> 
> <dedup>
> Elapsed time: out/host: 100 s
> mm_stat: 8832929792 3657329322 2832015360 0 2832015360 32609 0 952568877 80880336
> 
> It shows performance degradation roughly 13% and save 24% memory. Maybe,
> it is due to overhead of calculating checksum and comparison.

I like the patch set, and it makes sense. the benefit is, obviously,
case-by-case. on my system I've managed to save just 60MB on a 2.7G
data set, which is far less than I was hoping to save :)


I usually do DIRECT IO fio performance test. JFYI, the results
were as follows:

                     NO DEDUP    DEDUP
#jobs1                         	                
WRITE:               (586MB/s)	 (235MB/s)     
WRITE:               (535MB/s)	 (226MB/s)     
READ:                (415MB/s)	 (189MB/s)     
WRITE:               (416MB/s)	 (190MB/s)     
READ:                (382MB/s)	 (375MB/s)     
READ:                (312MB/s)	 (314MB/s)     
READ:                (197MB/s)	 (166MB/s)     
WRITE:               (197MB/s)	 (166MB/s)     
#jobs2                         	                
WRITE:              (1039MB/s)	 (447MB/s)     
WRITE:               (642MB/s)	 (262MB/s)     
READ:                (654MB/s)	 (337MB/s)     
WRITE:               (654MB/s)	 (337MB/s)     
READ:               (1444MB/s)	 (1184MB/s)    
READ:               (1291MB/s)	 (1140MB/s)    
READ:                (451MB/s)	 (223MB/s)     
WRITE:               (451MB/s)	 (224MB/s)     
#jobs3                         	                
WRITE:              (1175MB/s)	 (648MB/s)     
WRITE:               (678MB/s)	 (277MB/s)     
READ:                (921MB/s)	 (509MB/s)     
WRITE:               (921MB/s)	 (509MB/s)     
READ:               (1322MB/s)	 (1146MB/s)    
READ:               (1642MB/s)	 (1266MB/s)    
READ:                (583MB/s)	 (248MB/s)     
WRITE:               (582MB/s)	 (248MB/s)     
#jobs4                         	                
WRITE:              (1734MB/s)	 (878MB/s)     
WRITE:               (712MB/s)	 (291MB/s)     
READ:               (1298MB/s)	 (695MB/s)     
WRITE:              (1300MB/s)	 (695MB/s)     
READ:               (1885MB/s)	 (2197MB/s)    
READ:               (2908MB/s)	 (2256MB/s)    
READ:                (621MB/s)	 (268MB/s)     
WRITE:               (622MB/s)	 (268MB/s)     
#jobs5                         	                
WRITE:              (2260MB/s)	 (1104MB/s)    
WRITE:               (740MB/s)	 (296MB/s)     
READ:               (1578MB/s)	 (900MB/s)     
WRITE:              (1579MB/s)	 (901MB/s)     
READ:               (2378MB/s)	 (1969MB/s)    
READ:               (2573MB/s)	 (1753MB/s)    
READ:                (650MB/s)	 (275MB/s)     
WRITE:               (650MB/s)	 (275MB/s)     
#jobs6                         	                
WRITE:              (2907MB/s)	 (1331MB/s)    
WRITE:               (773MB/s)	 (299MB/s)     
READ:               (1733MB/s)	 (1010MB/s)    
WRITE:              (1734MB/s)	 (1011MB/s)    
READ:               (3010MB/s)	 (2465MB/s)    
READ:               (2715MB/s)	 (1772MB/s)    
READ:                (672MB/s)	 (280MB/s)     
WRITE:               (672MB/s)	 (280MB/s)     
#jobs7                         	                
WRITE:              (3098MB/s)	 (1526MB/s)    
WRITE:               (779MB/s)	 (299MB/s)     
READ:               (1800MB/s)	 (1151MB/s)    
WRITE:              (1800MB/s)	 (1151MB/s)    
READ:               (3294MB/s)	 (2765MB/s)    
READ:               (2861MB/s)	 (2031MB/s)    
READ:                (693MB/s)	 (283MB/s)     
WRITE:               (693MB/s)	 (283MB/s)     
#jobs8                         	                
WRITE:              (3425MB/s)	 (1739MB/s)    
WRITE:               (792MB/s)	 (302MB/s)     
READ:               (2003MB/s)	 (1289MB/s)    
WRITE:              (2004MB/s)	 (1289MB/s)    
READ:               (3901MB/s)	 (3218MB/s)    
READ:               (2954MB/s)	 (2297MB/s)    
READ:                (714MB/s)	 (285MB/s)     
WRITE:               (714MB/s)	 (286MB/s)     
#jobs9                         	                
WRITE:              (3744MB/s)	 (1944MB/s)    
WRITE:               (794MB/s)	 (303MB/s)     
READ:               (2038MB/s)	 (1400MB/s)    
WRITE:              (2040MB/s)	 (1401MB/s)    
READ:               (4159MB/s)	 (3583MB/s)    
READ:               (2963MB/s)	 (2425MB/s)    
READ:                (700MB/s)	 (286MB/s)     
WRITE:               (700MB/s)	 (286MB/s)     
#jobs10                        	                
WRITE:              (3863MB/s)	 (2122MB/s)    
WRITE:               (780MB/s)	 (304MB/s)     
READ:               (2059MB/s)	 (1551MB/s)    
WRITE:              (2060MB/s)	 (1552MB/s)    
READ:               (4573MB/s)	 (4004MB/s)    
READ:               (3025MB/s)	 (2271MB/s)    
READ:                (706MB/s)	 (287MB/s)     
WRITE:               (706MB/s)	 (287MB/s)     

                                   NO DEDUP                      DEDUP
jobs1                              perfstat         	                          
stalled-cycles-frontend      86,881,019,525 (  45.68%)	   95,848,055,454 (  44.71%)
stalled-cycles-backend       41,714,207,854 (  21.93%)	   44,958,946,213 (  20.97%)
instructions                179,619,952,260 (    0.94)	  208,777,551,585 (    0.97)
branches                     40,332,931,254 ( 669.275)	   46,951,257,852 ( 680.888)
branch-misses                   211,977,694 (   0.53%)	      227,694,865 (   0.48%)
jobs2                              perfstat         	                          
stalled-cycles-frontend     126,409,074,631 (  49.54%)	  151,381,853,397 (  50.04%)
stalled-cycles-backend       63,694,911,449 (  24.96%)	   75,662,875,621 (  25.01%)
instructions                237,127,811,965 (    0.93)	  278,316,276,728 (    0.92)
branches                     51,822,635,738 ( 597.433)	   60,986,851,952 ( 590.588)
branch-misses                   315,755,016 (   0.61%)	      347,424,093 (   0.57%)
jobs3                              perfstat         	                          
stalled-cycles-frontend     191,089,532,462 (  51.36%)	  231,335,643,820 (  52.60%)
stalled-cycles-backend       97,686,908,504 (  26.26%)	  120,989,629,180 (  27.51%)
instructions                331,602,259,024 (    0.89)	  381,383,314,335 (    0.87)
branches                     72,970,225,738 ( 539.030)	   84,708,904,219 ( 536.393)
branch-misses                   507,931,782 (   0.70%)	      518,364,954 (   0.61%)
jobs4                              perfstat         	                          
stalled-cycles-frontend     223,445,892,011 (  52.52%)	  249,360,340,619 (  53.35%)
stalled-cycles-backend      114,943,710,906 (  27.02%)	  128,993,039,366 (  27.60%)
instructions                380,626,111,963 (    0.89)	  414,605,021,230 (    0.89)
branches                     82,445,041,251 ( 536.219)	   89,259,825,600 ( 535.932)
branch-misses                   583,497,374 (   0.71%)	      588,281,124 (   0.66%)
jobs5                              perfstat         	                          
stalled-cycles-frontend     263,619,571,807 (  52.85%)	  321,088,781,157 (  54.21%)
stalled-cycles-backend      134,179,697,076 (  26.90%)	  167,682,863,875 (  28.31%)
instructions                443,228,511,108 (    0.89)	  507,399,916,840 (    0.86)
branches                     95,466,677,594 ( 532.379)	  110,214,238,221 ( 523.279)
branch-misses                   672,890,143 (   0.70%)	      730,685,294 (   0.66%)
jobs6                              perfstat         	                          
stalled-cycles-frontend     291,216,196,229 (  53.06%)	  368,134,629,095 (  54.77%)
stalled-cycles-backend      148,091,553,338 (  26.98%)	  196,277,284,992 (  29.20%)
instructions                490,912,765,147 (    0.89)	  568,687,905,057 (    0.85)
branches                    105,042,602,744 ( 532.627)	  123,581,871,771 ( 515.815)
branch-misses                   714,275,025 (   0.68%)	      795,739,846 (   0.64%)
jobs7                              perfstat         	                          
stalled-cycles-frontend     330,653,507,547 (  53.29%)	  408,847,632,764 (  54.82%)
stalled-cycles-backend      173,091,173,960 (  27.90%)	  225,113,359,025 (  30.18%)
instructions                551,239,096,548 (    0.89)	  634,980,768,831 (    0.85)
branches                    117,955,044,019 ( 531.343)	  137,597,472,747 ( 516.418)
branch-misses                   803,168,054 (   0.68%)	      890,836,684 (   0.65%)
jobs8                              perfstat         	                          
stalled-cycles-frontend     356,648,221,633 (  53.60%)	  430,630,870,321 (  54.78%)
stalled-cycles-backend      181,355,532,439 (  27.26%)	  225,833,853,276 (  28.73%)
instructions                591,082,455,684 (    0.89)	  675,551,813,173 (    0.86)
branches                    125,997,333,678 ( 530.684)	  145,611,739,589 ( 519.054)
branch-misses                   823,592,583 (   0.65%)	      934,474,711 (   0.64%)
jobs9                              perfstat         	                          
stalled-cycles-frontend     390,346,479,419 (  53.77%)	  464,669,227,714 (  54.83%)
stalled-cycles-backend      194,450,562,714 (  26.79%)	  231,567,413,546 (  27.32%)
instructions                645,446,764,508 (    0.89)	  732,189,754,115 (    0.86)
branches                    137,219,009,187 ( 529.491)	  157,387,961,718 ( 520.710)
branch-misses                   898,414,437 (   0.65%)	      990,118,876 (   0.63%)
jobs10                             perfstat         	                          
stalled-cycles-frontend     424,813,625,460 (  54.03%)	  504,229,836,920 (  54.93%)
stalled-cycles-backend      216,498,718,346 (  27.54%)	  264,019,747,607 (  28.76%)
instructions                698,139,050,494 (    0.89)	  791,700,475,394 (    0.86)
branches                    148,117,364,023 ( 527.254)	  170,053,726,692 ( 520.519)
branch-misses                   962,807,047 (   0.65%)	    1,065,430,885 (   0.63%)


                       NO DEDUP         DEDUP
seconds elapsed        63.480344573	97.971439666
seconds elapsed        58.655823065	110.635292879
seconds elapsed        73.470677655	139.499601409
seconds elapsed        78.538327853	150.636241458
seconds elapsed        87.074751505	177.352050355
seconds elapsed        96.067528245	200.932336337
seconds elapsed        107.100552618	223.780631440
seconds elapsed        114.803603478	244.200975111
seconds elapsed        127.158686582	267.434811513
seconds elapsed        139.436204098	291.221754828

	-ss