Re: Reduce function call costs on ELF platforms - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Reduce function call costs on ELF platforms
Date
Msg-id 20211124185559.mwyeeugivhu5fjbp@alap3.anarazel.de
Whole thread Raw
In response to Re: Reduce function call costs on ELF platforms  (Peter Eisentraut <peter.eisentraut@enterprisedb.com>)
Responses Re: Reduce function call costs on ELF platforms
List pgsql-hackers
Hi,

On 2021-11-23 17:28:08 +0100, Peter Eisentraut wrote:
> On 22.11.21 23:32, Tom Lane wrote:
> > > The easier approach for this class of issues is to use the linker option
> > > -Bsymbolic.
> > I don't recall details, but we've previously rejected the idea of
> > trying to use -Bsymbolic widely; apparently it has undesirable
> > side-effects on some platforms.  See commit message for e3d77ea6b
> > (hopefully there's some detail in the email thread [1]).  It sounds
> > like you're not actually proposing that, but I thought it would be
> > a good idea to note the hazard here.
> 
> Also, IIRC, -Bsymbolic was once frowned upon by packaging policies, since it
> prevents use of LD_PRELOAD.  I'm not sure what the current thinking there
> is, however.

It doesn't break some (most?) of the uses of LD_PRELOAD. In particular, it
doesn't break things like replacing the malloc implementation. When do you
have a symbol that you want to override *inside* your library (executables
already bind to their own symbols at compile time)? I've seen that for
replacing buggy functions in closed source things, but that's about it?

Greetings,

Andres Freund



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