Re: profiling connection overhead

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: profiling connection overhead
Date: 2010-11-24 19:30:47
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On Wed, Nov 24, 2010 at 1:20 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I tried configuring oprofile with --callgraph=10 and then running
> oprofile with -c, but it gives kooky looking output I can't interpret.

It looks like the trick is to compile with -fno-omit-frame-pointer.
New profiling run:

27563    10.3470           memset
15162     5.6917           memcpy
13471     5.0569  postgres                 hash_search_with_hash_value
13465     5.0547  postgres                 AllocSetAlloc
9513      3.5711           _int_malloc
8729      3.2768           fread
6336      2.3785             do_lookup_x
5788      2.1728             _dl_fixup
4995      1.8751  postgres                 MemoryContextAllocZero
4978      1.8687             strcmp

Full results, and call graph, attached.  The first obvious fact is
that most of the memset overhead appears to be coming from

Robert Haas
The Enterprise PostgreSQL Company
Attachment Content-Type Size
reconnect-callgraph.txt.bz2 application/x-bzip2 34.9 KB
reconnect-opreport.txt.bz2 application/x-bzip2 6.8 KB

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