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Re: Trying to understand ggc-page vs. ggc-simple
- To: msokolov at ivan dot Harhan dot ORG (Michael Sokolov)
- Subject: Re: Trying to understand ggc-page vs. ggc-simple
- From: Alexandre Oliva <aoliva at redhat dot com>
- Date: 29 Jan 2001 03:45:48 -0200
- Cc: gcc at gcc dot gnu dot org
- Organization: GCC Team, Red Hat
- References: <0101282103.AA19361@ivan.Harhan.ORG>
On Jan 28, 2001, msokolov@ivan.Harhan.ORG (Michael Sokolov) wrote:
> caring about page sizes and page alignment in ordinary user programs
> is completely useless and does nothing except wasting memory
Garbage collection can be done more efficiently if you can make sure
certain objects all live in the same page. I don't recall the
details, but I recall Mark Mitchell reported immense performance gains
when ensuring that memory chunks were kept page-aligned. You safe a
lot of page faults with that.
Laurynas Biveinis has been working on improving the memory-efficiency
of ggc-page on systems that have to use valloc(). The idea is to wrap
valloc() with some function that allocates large numbers of pages at a
time, and hands back aligned pages as requested.
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist *Please* write to mailing lists, not to me