Hi Janis,
[EMAIL PROTECTED] (Janis Johnson) wrote on 01.09.05 in <[EMAIL PROTECTED]>:
[quoteto.xps]
> On Thu, Sep 01, 2005 at 11:45:35PM +0200, Steven Bosscher wrote:
> > On Thursday 01 September 2005 23:19, girish vaitheeswaran wrote:
> > > Sorry I still did not follow. This is what I
> > > unde
Hello,
> > >you may try adding -fmove-loop-invariants flag, which enables new
> > >invariant motion pass.
> >
> > That cleaned up both my simplified test case, and the code it
> > originated from. It also cleaned up a few other cases where I
> > was noticing worse performance with FDO enabled.
On Friday 02 September 2005 00:53, Janis Johnson wrote:
> Girish started this thread about problems he is seeing with GCC 3.4.3
> (see http://gcc.gnu.org/ml/gcc/2005-07/msg00866.html). Others of us
> chimed in about similar issues with later versions. Suggestions for
> avoiding the problems have
On Thu, Sep 01, 2005 at 11:45:35PM +0200, Steven Bosscher wrote:
> On Thursday 01 September 2005 23:19, girish vaitheeswaran wrote:
> > Sorry I still did not follow. This is what I
> > understood. During Feedback optimization apart from
> > the -fprofile-generate, one needs to turn on
> > -fmove-lo
On Thursday 01 September 2005 23:19, girish vaitheeswaran wrote:
> Sorry I still did not follow. This is what I
> understood. During Feedback optimization apart from
> the -fprofile-generate, one needs to turn on
> -fmove-loop-invariants.
You don't "need to". It just might help iff you are using
Sorry I still did not follow. This is what I
understood. During Feedback optimization apart from
the -fprofile-generate, one needs to turn on
-fmove-loop-invariants. However this option is not
recognized by the gcc 3.4.4 or 3.4.3 compilers. What
am I missing?
-girish
--- Eric Christopher <[EMAIL
> >you may try adding -fmove-loop-invariants flag, which enables new
> >invariant motion pass.
>
> That cleaned up both my simplified test case, and the code it
> originated from. It also cleaned up a few other cases where I
> was noticing worse performance with FDO enabled. Thanks!!
>
> Perhap
On Aug 31, 2005, at 3:40 PM, girish vaitheeswaran wrote:
I do not see this flag in gcc3.4.4.
Am I missing something?
you may try adding -fmove-loop-invariants flag,
which enables new
invariant motion pass.
The "new invariant motion pass".
-eric
I do not see this flag in gcc3.4.4.
perflab2% gcc -o conftest -O3 -march=pentium4
-fmove-loop-invariants conftest.c
cc1: error: unrecognized command line option
"-fmove-loop-invariants"
Am I missing something?
-girish
--- Zdenek Dvorak <[EMAIL PROTECTED]>
wrote:
> Hello,
>
> > >A more likel
>you may try adding -fmove-loop-invariants flag, which enables new
>invariant motion pass.
That cleaned up both my simplified test case, and the code it
originated from. It also cleaned up a few other cases where I
was noticing worse performance with FDO enabled. Thanks!!
Perhaps this option sh
Hello,
> >A more likely source of performance degradation is that loop unrolling
> >is enabled when profiling, and loop unrolling is almost always a bad
> >pessimization on 32 bits x86 targets.
>
> To clarify, I was compiling with -funroll-loops and -fpeel-loops
> enabled in both cases.
>
> The
> Do you have specific testcase? It would be interesting to see if new
> optimizer can catch up at least on kill-loop branch.
Here is a simplified version of what I observed. In the non-FDO case,
the loop invariant load of the constant 32 is removed from the loop.
When FDO is enabled, the load r
I have tried with gcc 3.4.4 and still see the same
20%slowdown. If you folks are able to crack this, do
let me know. On my earlier attempts I had tried to
disable all of the flags that feedback optimization
turns on (except the ones that are turned on by
default) and still got the 20% slowdown.
Is
>
> There was some discussion a few weeks ago about some apps running slower
> with FDO enabled.
>
> I've recently investigated a similar situation using mainline. In my case,
> the fact that the loop_optimize pass is disabled during FDO was the cause
> of the slowdown. It appears that was rece
>A more likely source of performance degradation is that loop unrolling
>is enabled when profiling, and loop unrolling is almost always a bad
>pessimization on 32 bits x86 targets.
To clarify, I was compiling with -funroll-loops and -fpeel-loops
enabled in both cases.
The FDO slowdown in my case
On Tuesday 30 August 2005 17:53, Peter Steinmetz wrote:
> While this doesn't explain all of the degradations discussed (some were
> showing up on older versions of the compiler), it may explain some.
There is a lot of empirical evidence that the loop optimizer already
doesn't do many useful things
There was some discussion a few weeks ago about some apps running slower
with FDO enabled.
I've recently investigated a similar situation using mainline. In my case,
the fact that the loop_optimize pass is disabled during FDO was the cause
of the slowdown. It appears that was recently disabled
> Jan,
Hi,
> That's going to be rather difficult given that the app
> has over 1000 files. Is there a way I can turn off the
> "default" options one at a time ?
This is unforutnately not possible :( The optimizations used either
profile feedback or profile guessed by GCC itself. It looks like fo
Jan,
That's going to be rather difficult given that the app
has over 1000 files. Is there a way I can turn off the
"default" options one at a time ?
Thx
-girish
--- Jan Hubicka <[EMAIL PROTECTED]> wrote:
> > I have done quite a few experiments with this to
> > narrow down the problem. The perform
> I have done quite a few experiments with this to
> narrow down the problem. The performance numbers are
> slower compared to *No Feedback optimization with just
> -O3* Here are some of them. All the experiments were
> done on a new build-area in order to eliminate effects
> of old feedback files
I have done quite a few experiments with this to
narrow down the problem. The performance numbers are
slower compared to *No Feedback optimization with just
-O3* Here are some of them. All the experiments were
done on a new build-area in order to eliminate effects
of old feedback files.
1. I buil
I am using -O3. This is the only flag apart from the
profile flag -fprofile-use.
I had independently tried -march=pentium4 and that did
not buy any performance for this app.
-girish
--- Kelley Cook <[EMAIL PROTECTED]> wrote:
> > I started with a clean slate in my build
> environment
> > and di
I started with a clean slate in my build environment
and did not have any residual files hanging around.
Are the steps I have indicated in my earlier email
correct. Is there a way I can break down the problem
into a smaller sub-set of flags and eliminate the flag
causing the performance proble
> I started with a clean slate in my build environment
> and did not have any residual files hanging around.
> Are the steps I have indicated in my earlier email
> correct. Is there a way I can break down the problem
> into a smaller sub-set of flags and eliminate the flag
> causing the performance
I started with a clean slate in my build environment
and did not have any residual files hanging around.
Are the steps I have indicated in my earlier email
correct. Is there a way I can break down the problem
into a smaller sub-set of flags and eliminate the flag
causing the performance problem. Wh
> On Wed, Jul 20, 2005 at 10:45:01AM -0700, girish vaitheeswaran wrote:
> > > --- Steven Bosscher <[EMAIL PROTECTED]> wrote:
> > >
> > > > On Wednesday 20 July 2005 18:53, girish vaitheeswaran wrote:
> > > > > I am seeing a 20% slowdown with feedback optimization.
> > > > > Does anyone have any th
This is on Intel Pentium4 on Linux.
-girish
--- Janis Johnson <[EMAIL PROTECTED]> wrote:
> On Wed, Jul 20, 2005 at 10:45:01AM -0700, girish
> vaitheeswaran wrote:
> > > --- Steven Bosscher <[EMAIL PROTECTED]> wrote:
> > >
> > > > On Wednesday 20 July 2005 18:53, girish
> vaitheeswaran wrote:
>
On Wed, Jul 20, 2005 at 10:45:01AM -0700, girish vaitheeswaran wrote:
> > --- Steven Bosscher <[EMAIL PROTECTED]> wrote:
> >
> > > On Wednesday 20 July 2005 18:53, girish vaitheeswaran wrote:
> > > > I am seeing a 20% slowdown with feedback optimization.
> > > > Does anyone have any thoughts on th
I am using gcc 3.4.3
-girish
>
>
> --- Steven Bosscher <[EMAIL PROTECTED]> wrote:
>
> > On Wednesday 20 July 2005 18:53, girish
> > vaitheeswaran wrote:
> > > I am seeing a 20% slowdown with feedback
> > optimization.
> > > Does anyone have any thoughts on this.
> >
> > My first thought is th
On Wednesday 20 July 2005 18:53, girish vaitheeswaran wrote:
> I am seeing a 20% slowdown with feedback optimization.
> Does anyone have any thoughts on this.
My first thought is that you should probably first tell what compiler
you are using.
Gr.
Steven
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