[erlang-questions] why is mmap so darn difficult

Max Lapshin <>
Wed Jun 12 10:42:03 CEST 2013


I really don't know when mmap can be a good choice.

I thought that video streaming, when you need to read about half of
gigabyte per second from disk, repack it and write to network, is the
good place for mmap.
It was a mistake. If you get slow mmap disk read, than whole erlang
sticks and you get PHP-like performance when whole thread is blocked
for one client.


Perhaps in embedded mmap would be better when you want to save memory
and have 10 requests per day, but on high load mmap doesn't help.



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