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Hi Max, On 3/13/18 10:01 AM, Fischer, Max (SCC) wrote: > Hi all, > > I am rewriting some monitoring and trying to correctly digest the XrdXrootdMonBuff. However, the documentation [1] for XROOTD_MON_READU/_READV is unclear to me. > The docs suggest that one of the two is the "sum" of read operations for a readv, and the other is a sequence of individual read operations in a readv. However, *both* types are described as having multiple entires, being switched on by iov, and so on. The meaning of the flags implies READU is unpacked (i.e. a sequence of reads) whereas READV is not (i.e. entire read), but it is later mentioned that READV can also be followed by other READV of the same request. I think they only get split if there is no more room in the UDP buffer. > Is it safe to always construct a vector of READ entries for all adjacent READV/READU with the same info[].arg0.id[1], i.e. readv identifier? Hmmh, depends what you mean by adjacent :) I wouldn't bet on nothing else getting squeezed in between once a new UDP message needs to be created ... especially new 'u' or 'd' map massages. But as far as 't' stream goes, I believe they will be adjacent. Code for parsing of 't' stream messages in gled (it's hairy like hell but I guess you'd expect it to be): https://gist.github.com/osschar/de3f38af61087923735265b1a2a9e683#file-xrdmonsucker-cxx-L624 And XrdFile that accumulates monitoring information for each file: https://gist.github.com/osschar/de3f38af61087923735265b1a2a9e683#file-xrdfile-cxx-L161 https://gist.github.com/osschar/de3f38af61087923735265b1a2a9e683#file-xrdfile-cxx-L194 So, XrdFile has a state that allows it to check if it got all the messages (or missed some, UDP packets do get lost) for given seqid on every new update and on file close. Note that a single xrootd vector read request can read from several files at the same time ... not that anybody uses it ... but it might allow you to understand some wording in the documentation. Cheers, Matevz > Cheers, > Max > > [1] > http://xrootd.org/doc/dev44/xrd_monitoring.htm#_Toc449037000 > ######################################################################## > Use REPLY-ALL to reply to list > > To unsubscribe from the XROOTD-L list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1 > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1