Thanks Andy, Andreas!
Andreas told me this is a feature of async reading and that it gets sequential
if one sets readcachesize to 0.
Funny that I never printed offsets before :)
Cheers,
Matevz
On 11/13/12 10:04, Andrew Hanushevsky wrote:
> 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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