[Beowulf] MPICH ch_p4 compile vs runtime options - bufsize, pkt_size, socksize
bill at Princeton.EDU
Mon Aug 16 06:54:06 PDT 2004
Can anyone explain to me what the various options for MPICH compilation
versus what the runtime options would provide?
For example, when compiling MPICH-1.2.6 I have the options:
which state "changes the size of the socket buffers used."
allows you to choose the message length at which the ADI switches from
its short to long message format.
And for runtime I have:
a.out -p4sctrl bufsize=KBYTES
which controls the soket buffer size
The environment variables:
P4_SOCKBUFSIZE - defines the socket buffer size in bytes
Now in all cases I will also assume that the system-wide TCP settings
have also been increased (net.core.[rw]mem_max, net.ipv4.tcp_[ rw]mem)
in order to support sizes allowed in the above.
Except for optimizing -pkt_size I am under the belief that all the
others are effectively one and the same.
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