[Bug c++/21316] New: pointer lookup cache misses more frequent

[Bug c++/21316] New: pointer lookup cache misses more frequent

[kpmassey at gmail dot com]

The sample code runs 30-50% slower on my machine when compiled with 3.4.3 as
opposed to 3.3.4.  It creates some objects and then references them via pointer
lookup, so my best guess is that somehow 3.4.3 binaries have many more cache misses.

I have noticed the severe regression on AMD Athlon 3200 running linux 2.6, with
compile options -O3 -march=k8.  Other options (e.g. -O2 instead) don't help.

-- 
           Summary: pointer lookup cache misses more frequent
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kpmassey at gmail dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug c++/21316] pointer lookup cache misses more frequent

[kpmassey at gmail dot com]

------- Additional Comments From kpmassey at gmail dot com  2005-05-01 13:23 -------
Created an attachment (id=8781)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8781&action=view)
source file that illustrates problem


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug c++/21316] pointer lookup cache misses more frequent

[kpmassey at gmail dot com]

------- Additional Comments From kpmassey at gmail dot com  2005-05-01 13:25 -------
Created an attachment (id=8782)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8782&action=view)
.ii file from my compilation


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug c++/21316] pointer lookup cache misses more frequent

[kpmassey at gmail dot com]

------- Additional Comments From kpmassey at gmail dot com  2005-05-01 13:26 -------
Created an attachment (id=8783)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8783&action=view)
.s file from my compilation


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] pointer lookup cache misses more frequent

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |target
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4 Regression] pointer lookup cache misses more frequent

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2005-05-04 00:16 -------
Can you try with 4.0.0?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|pointer lookup cache misses |[3.4 Regression] pointer
                   |more frequent               |lookup cache misses more
                   |                            |frequent
   Target Milestone|---                         |3.4.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4 Regression] pointer lookup cache misses more frequent

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-04 01:16 -------
I could not reproduce this on a pentium4.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4 Regression] pointer lookup cache misses more frequent

[kpmassey at gmail dot com]

------- Additional Comments From kpmassey at gmail dot com  2005-05-04 01:20 -------
Subject: Re:  [3.4 Regression] pointer lookup cache misses more frequent

Actually, no.  Gentoo doesn't yet have 4.0.0 in portage, and being a
novice, I am reluctant to build myself.

On 4 May 2005 01:16:33 -0000, pinskia at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
> 
> ------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-04 01:16 -------
> I could not reproduce this on a pentium4.
> 
> --
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316
> 
> ------- You are receiving this mail because: -------
> You reported the bug, or are watching the reporter.
>


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4 Regression] pointer lookup cache misses more frequent

[mmitchel at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.4.4                       |3.4.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4/4.0/4.1 Regression] pointer lookup cache misses more frequent

[belyshev at depni dot sinp dot msu dot ru]

------- Additional Comments From belyshev at depni dot sinp dot msu dot ru  2005-05-22 22:14 -------
I can confirm this on amd64:

 gcc        avg. runtime
---------------------------
3.3.6		1.94
3.4.5		2.30
4.0.1		2.64
4.1.0		2.75


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|                            |3.4.5 4.0.1 4.1.0
      Known to work|                            |3.3.6
   Last reconfirmed|0000-00-00 00:00:00         |2005-05-22 22:14:54
               date|                            |
            Summary|[3.4 Regression] pointer    |[3.4/4.0/4.1 Regression]
                   |lookup cache misses more    |pointer lookup cache misses
                   |frequent                    |more frequent


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4/4.0/4.1 Regression] pointer lookup cache misses more frequent

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-22 21:13 -------
Moving to 4.0.2 pre Mark.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.4.5                       |4.0.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316

[Bug target/21316] [3.4/4.0/4.1 Regression] pointer lookup cache misses more frequent

[mmitchel at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.0.2                       |4.0.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21316