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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 >> >> ######################################################################## >> Use REPLY-ALL to reply to list >> >> To unsubscribe from the XROOTD-DEV list, click the following link: >> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-DEV&A=1 >> > > 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