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Whats the real penalty of non-mmap ggc?
- From: Kean Johnston <jkj at sco dot com>
- To: gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Wed, 12 Oct 2005 10:12:10 -0700
- Subject: Whats the real penalty of non-mmap ggc?
- Reply-to: jkj at sco dot com
After days spent trying to get a clean gmake check run, I am down to the
last few failures. They are all related to the PCH tests, and they all
fail the same way: "largefile.c:1: fatal error: had to relocate PCH".
Previously, *all* PCH tests were failing but I crafted a host file
that uses MAP_FIXED and now only this one test fails. However, if I
pretend that mmap() doesn't exist in ggc-page.c and fall back on
valloc, then everything passes. But the comments say that is not the
prefered solution. My question is: exactly what kind of penalty would
I pay if I forced the use of valloc() versus using mmap?
Any advice greatly appreciated.