| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | Alan Stange <stange(at)rentec(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: BG writer question? |
| Date: | 2005-08-11 16:43:05 |
| Message-ID: | 20050811164305.GB20172@alvh.no-ip.org |
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| Lists: | pgsql-performance |
On Thu, Aug 11, 2005 at 11:25:27AM -0400, Alan Stange wrote:
> why mmap and munmap each time? mmap and munmap are fairly expensive
> operations (on some systems), especially on multi cpu machines. munmap
> in particular generally needs to issue cross calls to the other cpus to
> ensure any page mappings are invalidated.
There are no mmap/munmap calls in our code. The problematic code is
probably somewhere in the libc. Maybe it'd be useful to figure out
where it's called and why, with an eye on working around that.
--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"I love the Postgres community. It's all about doing things _properly_. :-)"
(David Garamond)
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