Hi,

I'm testing the monitoring collector extension that is capable of storing full
access details into a root tree. Running a simple xrdcp I realized that xrdcp
first copies data at offset of 8MB and only then the beginning of the file.

t ~ time since file open
l ~ length of request
o ~ offset

// file_len=4983779
SXrdIoInfo::Dump() N_reqs = 2, N_vec_read_subreqs = 0
   0 Read t=2 l=483 o=4983296
   1 Read t=4 l=4983296 o=0

// file_len=9311384
SXrdIoInfo::Dump() N_reqs = 2, N_vec_read_subreqs = 0
   0 Read t=2 l=922776 o=8388608
   1 Read t=4 l=8388608 o=0

This is even funnier for a larger file (~400MB) ... the first 8MB (offset=0) are
read after 238MB are already read, see below, entry 60.

What's the secret here? :)

Cheers,
Matevz

// file_len=428002641
SXrdIoInfo::Dump() N_reqs = 102, N_vec_read_subreqs = 0
   0 Read t=5 l=4194304 o=8388608
   1 Read t=10 l=4194304 o=12582912
   2 Read t=20 l=4194304 o=16777216
   3 Read t=35 l=4194304 o=20971520
   4 Read t=45 l=4194304 o=25165824
   5 Read t=55 l=4194304 o=29360128
   6 Read t=65 l=4194304 o=33554432
   7 Read t=75 l=4194304 o=37748736
   8 Read t=85 l=4194304 o=41943040
   9 Read t=95 l=4194304 o=46137344
  10 Read t=105 l=4194304 o=50331648
  11 Read t=115 l=4194304 o=54525952
  12 Read t=130 l=4194304 o=58720256
  13 Read t=140 l=4194304 o=62914560
  14 Read t=155 l=4194304 o=67108864
  15 Read t=165 l=4194304 o=71303168
  16 Read t=170 l=4194304 o=75497472
  17 Read t=180 l=4194304 o=79691776
  18 Read t=190 l=4194304 o=83886080
  19 Read t=205 l=4194304 o=88080384
  20 Read t=215 l=4194304 o=92274688
  21 Read t=225 l=4194304 o=96468992
  22 Read t=240 l=4194304 o=100663296
  23 Read t=255 l=4194304 o=104857600
  24 Read t=260 l=4194304 o=109051904
  25 Read t=265 l=4194304 o=113246208
  26 Read t=275 l=4194304 o=117440512
  27 Read t=285 l=4194304 o=121634816
  28 Read t=295 l=4194304 o=125829120
  29 Read t=305 l=4194304 o=130023424
  30 Read t=315 l=4194304 o=134217728
  31 Read t=325 l=4194304 o=138412032
  32 Read t=335 l=4194304 o=142606336
  33 Read t=345 l=4194304 o=146800640
  34 Read t=360 l=4194304 o=150994944
  35 Read t=370 l=4194304 o=155189248
  36 Read t=375 l=4194304 o=159383552
  37 Read t=385 l=4194304 o=163577856
  38 Read t=390 l=4194304 o=167772160
  39 Read t=400 l=4194304 o=171966464
  40 Read t=405 l=4194304 o=176160768
  41 Read t=420 l=4194304 o=180355072
  42 Read t=425 l=4194304 o=184549376
  43 Read t=435 l=4194304 o=188743680
  44 Read t=445 l=4194304 o=192937984
  45 Read t=455 l=4194304 o=197132288
  46 Read t=465 l=4194304 o=201326592
  47 Read t=475 l=4194304 o=205520896
  48 Read t=485 l=4194304 o=209715200
  49 Read t=495 l=4194304 o=213909504
  50 Read t=505 l=4194304 o=218103808
  51 Read t=515 l=4194304 o=222298112
  52 Read t=525 l=4194304 o=226492416
  53 Read t=535 l=4194304 o=230686720
  54 Read t=540 l=4194304 o=234881024
  55 Read t=550 l=4194304 o=239075328
  56 Read t=560 l=4194304 o=243269632
  57 Read t=575 l=4194304 o=247463936
  58 Read t=580 l=4194304 o=251658240
  59 Read t=590 l=4194304 o=255852544
  60 Read t=605 l=8388608 o=0
  61 Read t=625 l=4194304 o=260046848
  62 Read t=635 l=4194304 o=264241152
  63 Read t=645 l=4194304 o=268435456
  64 Read t=655 l=4194304 o=272629760
  65 Read t=665 l=4194304 o=276824064
  66 Read t=675 l=4194304 o=281018368
  67 Read t=680 l=4194304 o=285212672
  68 Read t=690 l=4194304 o=289406976
  69 Read t=695 l=4194304 o=293601280
  70 Read t=705 l=4194304 o=297795584
  71 Read t=715 l=4194304 o=301989888
  72 Read t=730 l=4194304 o=306184192
  73 Read t=745 l=4194304 o=310378496
  74 Read t=760 l=4194304 o=314572800
  75 Read t=770 l=4194304 o=318767104
  76 Read t=780 l=4194304 o=322961408
  77 Read t=790 l=4194304 o=327155712
  78 Read t=800 l=4194304 o=331350016
  79 Read t=810 l=4194304 o=335544320
  80 Read t=820 l=4194304 o=339738624
  81 Read t=825 l=4194304 o=343932928
  82 Read t=835 l=4194304 o=348127232
  83 Read t=850 l=4194304 o=352321536
  84 Read t=855 l=4194304 o=356515840
  85 Read t=870 l=4194304 o=360710144
  86 Read t=880 l=4194304 o=364904448
  87 Read t=895 l=4194304 o=369098752
  88 Read t=905 l=4194304 o=373293056
  89 Read t=915 l=4194304 o=377487360
  90 Read t=925 l=4194304 o=381681664
  91 Read t=935 l=4194304 o=385875968
  92 Read t=940 l=4194304 o=390070272
  93 Read t=950 l=4194304 o=394264576
  94 Read t=970 l=4194304 o=398458880
  95 Read t=975 l=4194304 o=402653184
  96 Read t=985 l=4194304 o=406847488
  97 Read t=995 l=4194304 o=411041792
  98 Read t=1005 l=4194304 o=415236096
  99 Read t=1010 l=4194304 o=419430400
100 Read t=1025 l=4194304 o=423624704
101 Read t=1030 l=183633 o=427819008

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