fix exp daily commits using git log --first-parent

Without this option daily commits visibly alternated between two
branches, creating huge diffs at each switch, and causing the data to be
misleading.

3 files changed, 88 insertions, 79 deletions

diff --git a/README.md b/README.md
index 27dcd44..9135b58 100644
--- a/README.md
+++ b/README.md
@@ -152,7 +152,7 @@ l'ensemble des fichiers.
 
 ### Bases de comparaison
 
-Pour évaluer les performances du système DNA-Backup, trois autres systèmes de
+Pour évaluer les performances du système DNA-Backup, quatre autres systèmes de
 stockage versionnés ont été choisis comme base de comparaison :
 
 - **Git diffs**
@@ -276,78 +276,78 @@ Commits journaliers :
 
 ```
 =============================== SUMMARY ===============================
-      dna_4k       dna_8k        diffs       nopack        targz           real
-  66,399,072   60,446,750   47,304,261   63,594,844   47,877,584    202,628,344
-  21,873,958   24,422,316    9,911,248   43,598,822   50,529,069    214,276,336
-       4,724        4,747        1,175       26,968   50,529,943    214,278,164
-     347,460      242,271    9,912,728       76,072   47,893,781    202,636,078
-     159,814       16,899        3,307       56,203   47,894,249    202,639,214
-   2,918,706    2,762,164    9,911,148       41,606   50,531,041    214,283,553
-     349,216      253,022    9,910,361      139,911   47,890,923    202,641,133
-   2,865,631    2,794,693    9,912,341       69,243   50,530,875    214,285,297
-     233,171        2,504          214        9,789   50,531,578    214,285,426
-     343,483      234,834    9,914,620       13,703   47,894,718    202,641,398
-     833,810      871,476      266,905    4,764,839   47,843,104    202,455,083
-     237,510      270,660      142,110    1,976,823   47,793,819    202,272,761
-     167,305       87,432       18,611        6,256   47,791,775    202,244,796
-         113          140          289        2,009   47,791,778    202,244,779
-   2,930,957    2,796,716   10,165,351       64,393   50,534,975    214,286,010
-      20,364       32,883        7,841       48,219   50,533,061    214,283,569
-     351,923      235,867    9,923,334      117,287   47,896,130    202,642,396
+     dna_4k       dna_8k        diffs       nopack         targz           real
+ 66,026,534   60,083,471   47,011,621   63,237,214    47,582,036    201,476,675
+      8,010       12,882        2,625       88,673    47,580,422    201,472,392
+  8,368,117    9,854,802    3,270,798   26,668,802    48,699,094    206,006,230
+    203,941      107,870          496       24,839    48,699,144    206,006,227
+    214,572      121,041        1,475      318,053    48,699,266    206,006,571
+    254,132      161,759    3,271,631      107,651    47,592,358    201,472,618
+    419,776      395,453       99,337    2,758,951    47,579,804    201,420,809
+     72,677       86,780      127,793      561,940    47,578,309    201,415,269
+    153,987       75,273       19,221       10,035    47,590,552    201,467,847
+    299,196      224,155      250,581    1,203,018    47,719,274    202,032,972
+     40,413       39,673       19,555      550,478    47,721,098    202,042,129
+    158,232       79,739          203       45,564    47,721,112    202,042,114
+    182,559      116,565       12,419      284,765    47,725,696    202,057,720
+     12,368       13,040        5,823       76,010    47,731,040    202,065,875
+     23,134       28,412       13,370      528,743    47,738,360    202,078,613
+     26,724       33,395       10,837      374,955    47,735,904    202,078,276
+     71,352       84,410       69,707      498,918    47,771,130    202,216,013
 ================================ TOTAL ================================
- 100,037,217   95,475,374  127,305,844  114,606,987  832,288,403  3,525,024,337 
+ 76,535,724   71,518,720   54,187,492   97,338,609   813,464,599  3,443,358,350
 ```
 
 Commits hebdomadaires :
 
 ```
 =============================== SUMMARY ===============================
-        dna_4k         dna_8k          diffs         nopack           real
-    70,192,809     63,852,374     49,917,523     67,132,003    214,292,720
-        31,567         28,668          8,822         90,423    214,301,810
-        27,389         31,485         10,920         99,194    214,299,953
-    18,135,507     20,861,135      9,918,650     40,011,293    202,624,903
-       907,939      1,209,389        285,459      4,920,733    202,470,023
-       113,871        152,351        293,731        137,519    202,618,267
-       294,810        367,701        272,263      2,304,224    203,092,308
-     2,112,921      2,540,859      1,148,513      9,636,016    201,476,675
-       252,068        288,241        609,369        857,331    202,282,568
-       782,812        981,296        697,995      2,758,951    201,420,809
-       136,493        161,325        398,494        727,346    202,065,360
-        62,677         80,290        134,441        458,130    202,251,722
-       162,061        196,716        365,229        230,404    202,465,009
-         7,665          9,678         10,625         77,034    202,457,471
-        71,731         80,298        152,999        187,241    202,615,704
-       307,109        222,474        241,092         12,081    203,083,912
-       305,795        228,540         35,494        740,246    203,113,279
+     dna_4k       dna_8k        diffs       nopack         targz           real
+ 65,996,508   60,066,667   47,003,541   63,221,563    47,569,933    201,420,809
+    889,756      985,651      395,080    6,358,050    47,723,749    202,065,875
+  8,109,685    9,714,907    2,994,599   25,581,925    48,700,415    206,003,757
+    205,101      108,968          407       50,815    48,700,637    206,003,795
+    225,841      144,120        8,679      401,381    48,698,820    206,005,265
+  1,657,786    2,050,048      579,422    6,943,222    48,733,791    206,098,060
+  1,206,672    1,495,828      360,710    4,799,958    48,840,759    206,648,359
+  1,926,509    2,385,637      738,359    4,983,831    48,892,096    206,834,840
+  2,263,134    2,498,842    1,389,502    7,767,439    49,297,747    209,328,856
+    592,440      861,038      146,129    2,899,286    49,331,055    209,479,362
+    198,407      264,136       47,436    1,385,568    49,333,845    209,503,564
+    155,538      266,689       37,183    1,808,603    49,338,373    209,509,777
+    102,087      136,482       23,924    1,555,868    49,336,559    209,515,352
+  4,044,866    4,845,345    1,404,256   11,037,484    49,933,159    211,878,380
+  6,529,456    7,605,526    2,326,692   17,577,030    50,214,110    212,941,025
+  1,258,880    1,658,700      304,617    6,594,520    50,293,382    213,254,405
+    840,200    1,051,378      258,512    4,016,395    50,398,489    213,650,745
 ================================ TOTAL ================================
-    93,905,224     91,292,820     64,501,619    130,380,169  3,476,932,493 
+ 96,202,866   96,139,962   58,019,048  166,982,938   835,336,919  3,540,142,226 
 ```
 
 Commits mensuels :
 
 ```
 =============================== SUMMARY ===============================
-        dna_4k         dna_8k          diffs         nopack           real
-    66,344,139     60,414,327     47,255,410     63,531,013    202,455,244
-       268,382        293,432         71,579      2,114,221    202,438,437
-       288,294        288,397        137,081      2,625,834    202,477,165
-     2,617,048      2,989,196      1,106,365     11,273,622    203,355,330
-     4,219,402      5,065,795      1,485,211     14,062,635    206,087,365
-     6,925,148      8,177,404      3,102,478     20,489,609    209,450,906
-     1,931,351      2,314,294        771,998      6,811,409    209,646,120
-     9,775,191     11,577,926      3,335,990     26,532,154    213,287,798
-     7,783,071      9,101,660      2,505,353     20,687,252    216,420,188
-     9,445,609     10,977,253      3,479,709     25,758,937    217,852,953
-       701,911        905,423        164,682      4,517,360    217,851,223
-    14,385,992     16,467,969      4,380,280     32,949,448    222,875,080
-     3,389,340      4,347,527        817,894     14,054,849    223,352,903
-    13,307,722     15,446,179      4,060,874     32,889,854    225,760,003
-     3,219,293      3,895,349      1,301,487     10,953,334    225,577,911
-     1,876,709      2,451,988        390,110      9,171,030    225,848,365
-    12,995,018     15,561,939      4,204,779     32,837,755    227,575,213
+     dna_4k       dna_8k        diffs       nopack         targz           real
+ 67,749,414   61,662,329   48,249,466   64,900,653    48,828,605    206,662,692
+  2,396,108    2,454,980    1,495,969    7,407,714    48,900,735    206,964,143
+  1,953,606    2,180,048      797,390    9,856,043    49,326,511    209,515,646
+ 10,598,329   12,226,656    4,142,700   28,400,251    50,394,403    213,653,996
+ 14,285,731   16,520,326    5,489,832   34,132,686    51,315,648    217,862,957
+  7,761,827    8,683,938    2,262,584   19,233,445    51,941,615    220,756,834
+ 10,116,837   12,628,400    2,999,817   28,983,950    52,574,107    223,306,219
+  1,457,911    1,901,545      299,628    8,343,393    52,587,994    223,373,786
+ 14,563,753   16,805,176    4,759,088   34,259,652    53,210,823    226,113,059
+  2,313,331    2,886,878      679,794   10,029,012    53,165,063    225,781,616
+    765,371    1,003,047      138,547    4,375,159    53,183,197    225,870,650
+ 17,011,965   20,527,210    5,142,691   45,544,733    53,842,821    228,546,001
+  1,415,857    1,831,671      247,526    8,491,133    53,876,401    228,653,615
+  7,445,399    8,214,306    2,333,317   18,119,613    54,605,555    232,014,492
+ 13,079,884   15,834,194    3,989,065   37,945,661    55,206,806    234,571,285
+ 13,890,556   16,436,758    3,800,775   37,509,079    56,059,067    238,170,923
+ 11,523,815   13,696,636    3,030,148   32,387,325    56,716,443    241,420,002
 ================================ TOTAL ================================
-   159,473,620    170,276,058     78,571,280    331,260,316  3,652,312,204 
+198,329,694  215,494,098   89,858,337  429,919,502   895,735,794  3,803,237,916
 ```
 
 <!-- LTeX: language=en -->
diff --git a/exp/Makefile b/exp/Makefile
index 8b7ce5c..e7c104a 100644
--- a/exp/Makefile
+++ b/exp/Makefile
@@ -1,14 +1,21 @@
-REPO_URL  := https://club1.fr/~nicolas/git/dna-backup/
-
 SHELL := /bin/bash
 
+################# Principal parameters #################
+
+REPO_URL     ?= https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
+REPO_BRANCH  ?= master
+RANGE        ?= daily
+# Number of initial commits to skip. This option has been added for the
+# Linux kernel repo, as the first commits are too far away date wise.
+SKIP_COMMITS ?= 0
+
 # Reset LC_NUMERIC to make printf thousands separator work as expected
 export LC_NUMERIC  :=
 
 export DNA_BACKUP  ?= ../dna-backup
 export DNA_PARAMS  ?= dna_params
 export MAX_VERSION ?= 5
-export COMMITS     ?= commits.daily
+export COMMITS     ?= commits.$(RANGE)
 DNA_4K             ?= dna_4k
 DNA_8K             ?= dna_8k
 NOPACK             ?= nopack
@@ -21,10 +28,6 @@ export REPO_PATH   ?= repo
 export GIT_PATH    ?= $(abspath git)
 GITC      := git -C $(REPO_PATH)
 
-# Number of initial commits to skip. This option has been added for the
-# Linux kernel repo, as the first commits are too far away date wise.
-SKIP_COMMITS ?= 30
-
 DNADIRS   := $(DNA_4K) $(DNA_8K)
 DATADIRS  := $(DNA_4K) $(DNA_8K) $(DIFFS) $(NOPACK) $(TARGZ) $(REAL)
 SIZEFILES := $(DATADIRS:%=%.size)
@@ -65,7 +68,7 @@ $(NOPACK).size: $(NOPACK).versions run
 		| bc \
 		>> $@; \
 		prev=$$i; \
-        done
+	done
 
 %.size: % run
 	find $< -type f -exec du -ba {} + | sort -k2 | cut -f1 > $@
@@ -105,16 +108,21 @@ $(DATADIRS) $(NOPACK).versions $(REAL).versions:
 $(DNA_BACKUP): .FORCE
 	@$(MAKE) -C $(@D) --no-print-directory $(@F)
 
+.INTERMEDIATE: commits.monthly
 commits.monthly: commits.daily
 	sed -n '0~30p' $< > $@
 
+.INTERMEDIATE: commits.weekly
 commits.weekly: commits.daily
 	sed -n '0~7p' $< > $@
 
-commits.daily: | repo git
-	$(GITC) log --reverse --no-merges --pretty=tformat:"%H	%as" \
+.INTERMEDIATE: commits.daily
+commits.daily: commits
+	tail -n +$(SKIP_COMMITS) $< > $@
+
+commits: | repo git
+	$(GITC) log $(REPO_BRANCH) --reverse --date-order --first-parent --pretty=tformat:"%H	%as" \
 	| sort --unique --key=2 \
-	| tail -n +$(SKIP_COMMITS) \
 	> $@
 
 repo git &:
@@ -125,11 +133,11 @@ repo git &:
 .PHONY: clean
 clean: mostlyclean
 	rm -rf $(REPO_PATH) $(GIT_PATH)
-	rm -f commits.*
+	rm -f commits
 
 mostlyclean: resultsclean
 	rm -rf $(DATADIRS) $(DATADIRS:%=%.versions)
-	rm -f run $(DATADIRS:%=%.results) $(DNA_PARAMS)
+	rm -f run $(DATADIRS:%=%.results) $(DNA_PARAMS) commits.*
 
 resultsclean:
 	rm -f summary.csv $(SIZEFILES)
diff --git a/exp/README.md b/exp/README.md
index 1437aea..2ad6ece 100644
--- a/exp/README.md
+++ b/exp/README.md
@@ -4,7 +4,7 @@
 
 ```bash
 # run experiences
-make [SKIP_COMMITS=<count>] [MAX_VERSION=<count>] [COMMITS=<file>]
+make [SKIP_COMMITS=<count>] [MAX_VERSION=<count>] [RANGE=<range>]
 
 # clean results
 make mostlyclean
@@ -13,12 +13,13 @@ make mostlyclean
 make clean
 ```
 
-Les 3 fichiers de commits suivants peuvent être automatiquement générés :
+`<range>` can be one of these: 
+- `daily`
+- `weekly`
+- `monthly`
 
-- `commits.daily`
-- `commits.weekly`
-- `commits.monthly`
+By default:
 
-Par défaut les 30 premiers commits journaliers sont skippés, le nombre
-max de version utilisés pour l'expérience est 5 et le fichier
-`commits.daily` est utiliser comme source de commits.
+- `SKIP_COMMITS` = 0
+- `MAX_VERSION` = 5
+- `RANGE` = daily