Test with srmcp of 196 MB file: for ifconfig got size of 204.9... OK

Using standard PAT:

  dcap-read dcap-readv tstoragefile-read tstoragefile-read-actual tstoragefile-read-cache tstoragefile-readv-actual from IFCONFIG
std, 1 file 36.32 / 36.32 36.32 / / 245.23
cache=20MB, 1 file 2.3 217.735 36.32 2.3 33.99 217.735 285.56
patched4, cache=20MB, 1 file 98.6723 / 36.327 98.6723 31.0044 / 145
cache=20MB, 10k events 69.1704 9032.86 1384 69.1704 1314.83 9032.86 11451.0
patched4, cache=20MB, 10k events 3857.27 / 1384 3857.27 1183.52 / 5540.3

  • PAT_WN08_PSI_network_1file_1_commented.png: "srmcp" is the copy to local area of a file from the SE (196 MB), can be used as reference
    PAT_WN08_PSI_network_1file_1_commented.png

  • PAT_WN08_PSI_network_10kevts_CACHE20_patch4_commented.png:
    PAT_WN08_PSI_network_10kevts_CACHE20_patch4_commented.png

seems that using rh auto-detect for dcache selects the buffering:

http://cmslxr.fnal.gov/lxr/source/Utilities/DCacheAdaptor/plugins/DCacheStorageMaker.cc#038

http://cmslxr.fnal.gov/lxr/source/Utilities/DCacheAdaptor/src/DCacheFile.cc#132

126   // Turn off read-ahead, or adjust read-ahead size depending on
127   // whether buffering has been requested.  This is a very tricky
128   // balance here.  Without read-ahead data processing appears to
129   // become exceedingly slow, and with default (1MB) read-ahead
130   // it appears to saturate disk servers and network.  Try tread
131   // reasonable middle ground here.
132   if (flags & IOFlags::OpenUnbuffered)
133     dc_noBuffering(m_fd);
134   else
135     dc_setBufferSize(m_fd, 64000);
136 

-- LeonardoSala - 22-Jan-2010

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Topic revision: r5 - 2010-01-25 - unknown
 
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