Re: PATCH: fail to improve psymtab memory consumption

[Daniel Berlin <dan at cgsoftware dot com>]

Andrew Cagney <ac131313@cygnus.com> writes:

>>> Does this require serial or random file i/o?
>> ... you could make fread use mmap
>> in special cases, but they don't happen enough in practice to make
>> fread fast enough to beat mmap.
> 
> 
> It may not happen enough to ``beat mmap'', it certainly happens enough
> to justify the implementation of FILE using V/M based schema.
Err, what?
You must not have looked at most pieces of software that access disk
these days. Most use mmap when possible.
> 
> Anyway, that isn't the objective.  The objective is to get the dwarf2
> reader clean simple and pragmatically fast.  Fast, at all cost, is
> like micro-optomizing using STREQ() macros.

Which i'm opposed to completely, and you know this (I replaced quite a
few when a lot of STREQ->strcmp_iw changes went in, instead of
STREQ->STREQ_IW)

Comparing using MMAP to micro-optimizing is trivializing it in the extreme.
If you really think it's a micro optimization, once again, I invite
you to *try* it.

>If you think there should
> be a mmap implementation then abstract it out so that dwarf2 uses it
> rather than contains it.

It does.
If configure says we have MMAP, we use MMAP.

What's the problem?
Where do you think this abstraction should take place? BFD?

> 
> If you think there should be MMAP, then get it added to BFD where all
> readers will benefit, not just DWARF2.

This is tricky, because of the hell that is BFD.
Apple's tried it, i've tried it, etc.
Because of hacks and kludges for in-memory stuff in BFD, it breaks
things.

>

> 
> 	Andrew

-- 
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Boy With Pail...  Kitten On Fire.
"-Steven Wright