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Re: bigcore.exp on 64-bit systems
- From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- To: mark dot kettenis at xs4all dot nl (Mark Kettenis)
- Cc: eliz at gnu dot org, gdb at sourceware dot org
- Date: Sat, 13 Jan 2007 19:31:35 +0100 (CET)
- Subject: Re: bigcore.exp on 64-bit systems
Mark Kettenis wrote:
> 2.6.16 certainly qualifies as modern. The idea is that the test will
> create a sparse core file, that will take up almost no disk space.
> But the fact that it takes more than 600 seconds to dump the core file
> (that's the cause of the SIGABRT timeout), suggests that it isn't
> doing that.
The problem I've seen on certain Linux kernel versions is that while
generating the core file, the kernel fully populates the page tables
spanning the (zero) heap allocated by the bigcore test.
This means that while it doesn't allocate memory (or disk space) for
the heap itself, it will allocate non-pageable memory for the page
tables, and if the heap gets to several TB, that means several GB
of page tables.
To circumvent this, I generally set a reasonable ulimit -v limit
before running the test suite on a 64-bit system.
Bye,
Ulrich
--
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE
Ulrich.Weigand@de.ibm.com