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Hi Andy, > > The way I read the graph is that when you put a bigger load on the > proxy server it slows down. I wouldn't think that is unusual. The > proxy machine may be overloaded at that point. It's unlikely to be the > nic because we know that it can do at least 360mbps. So it might be > the CPU (easy to check). Alternatively, it could be the disk drive at > the end point that is overloaded with 300 jobs. > The proxy server had low CPU load. I did not check disk IO, but I guess this is negligible because caching on the proxy was not enabled, neither disk nor memory ... also, no prefetching of any kind. > But let's say the above isn't the case because 300 jobs in single read > perform better than 150 jobs in single read. That would point to the > fact that either proxy is unrolling the vector reads or that the > server is unrolling them. I suspect both because the readv passthrough > is not available until Release 4 which has not been released yet. > Sever-side unrolling, as unpleasant as it is, would not show such an > effect but proxy-side unrolling most certainly would. > > The take-away: try the test again with a proxy server based on git head. I run proxy test from master branch, which I updated 34 days ago. I will run the same set of jobs from the machine where the proxy was running directly to the data servers (mostly at FNAL) to make sure the problem is really in the proxy server. Thanks, Alja > On Tue, 21 Jan 2014, Alja Mrak-Tadel wrote: > >> Hi, >> >> There was an issue at RAL T1 where they are trying to use proxy >> server as their nodes do not have outgoing connectivity. >> >> Trying to reproduce this at UCSD, I have been running test on a proxy >> server without any caching using the following configuration file: >> http://uaf-2.t2.ucsd.edu/~alja/onlyproxy.cfg >> >> >> On the plot http://uaf-2.t2.ucsd.edu/~matevz/tmp/traffic.png is >> network traffic of the proxy server during four consecutive tests: >> - 300 jobs reading 2.4MB every 10s in 128 chunk-vector-read >> - 300 jobs reading 2.4MB every 10s in a single read >> - 150 jobs reading 2.4MB every 10s in a single read >> - 150 jobs reading 2.4MB every 10s in 128 chunk-vector-read >> >> >> Is there something obvious that we missed in the configuration of >> proxy-only server? How should we go about trying to find the >> bottlenecks here? >> >> Thanks, >> Alja >> >> ######################################################################## >> 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 >> ######################################################################## 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