Hi Matevz,
This is a known problem. Yes, it bizzare but it is what it is. We will
have to wait for 4.0 when we deploy the new client and the new xrdcp which
should solve this problem. I agree, it's a real problem.
Andy
On Mon, 12 Nov 2012, Matevz Tadel wrote:
> 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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