[petsc-users] Question - about the 'Hint for performance tuning'
김성익
ksi2443 at gmail.com
Tue Jan 3 06:22:42 CST 2023
2023년 1월 3일 (화) 오후 8:55, Matthew Knepley <knepley at gmail.com>님이 작성:
> On Tue, Jan 3, 2023 at 12:48 AM 김성익 <ksi2443 at gmail.com> wrote:
>
>> I got more questions so I resend this email with more questions.
>>
>> 1.After reconfigure by
>> ./arch-main-debug/lib/petsc/conf/reconfigure-arch-main-debug.py
>> --with-debugging=0 --PETSC_ARCH=arch-main-opt ,
>> I tried to build my code.
>>
>> But I got an error as below
>> [image: image.png]
>> How can I fix this?
>>
>
> You reconfigured with PETSC_ARCH=arch-main-opt, but your build is using
> "arch-linux-c-opt". Why are you changing it?
>
At first Matthew told me use
'./arch-main-debug/lib/petsc/conf/reconfigure-arch-main-debug.py
--with-debugging=0 --PETSC_ARCH=arch-main-opt' for build optimized.
However, I got an error the error is as below.
[image: image.png]
So Barry told me : "The previous value of PETSC_ARCH was not
arch-main-debug do ls $PETSC_DIR and locate the directory whose name begins
with arch- that will tell you the previous value used for PETSC_ARCH."
So I used
"./arch-linux-c-debug/lib/petsc/conf/reconfigure-arch-linux-c-debug.py
--with-debugging=0 --PETSC_ARCH=arch-linux-c-opt"
That command worked. However I got an error when I build my code and the
error is as below.
[image: image.png]
>
>>
>> 2.
>>
>> CFLAGS = -O3
>> FFLAGS =
>> CPPFLAGS =
>> FPPFLAGS =
>> COPTFLAGS = -march=native
>>
>>
>> app : a1.o a2.o a3.o a4.o
>> $(LINK.C) -o $@ $^ $(LDLIBS)
>>
>>
>> include ${PETSC_DIR}/lib/petsc/conf/rules
>> include ${PETSC_DIR}/lib/petsc/conf/test
>>
>> Upper makefile is just for build my own code not for src of petsc.
>> In this case, also has problem as your comments?
>>
>
> I do not understand your question.
>
My questions is :
When building my own code without reconfigure of PETSc, I wonder if there
will be performance improvement by building with the high optimization
level of compiler even if the makefile is configured as above.
>
>
>>
>> 3. I have no such processors. Where can I find benchmark information
>> about STREAMS?
>> I mean I don't have such various processors. So I just wondering the
>> results of STREAMS each processors (already existing results of various
>> processors).
>> Can anyone have results of benchmark of various desktop systems?
>>
>
> There are catalogues of STREAMS results online.
>
Sorry, I can't find proper catalogues. What's the keyword for googling or
could you please give a link of catalogues?
Thanks,
Hyung Kim
>
> Thanks,
>
> Matt
>
>
>> Thanks,
>> Hyung Kim
>>
>>
>>
>>
>>
>> 2023년 1월 3일 (화) 오후 2:19, 김성익 <ksi2443 at gmail.com>님이 작성:
>>
>>> After reconfigure by
>>> ./arch-main-debug/lib/petsc/conf/reconfigure-arch-main-debug.py
>>> --with-debugging=0 --PETSC_ARCH=arch-main-opt ,
>>> I tried to build my code.
>>>
>>> But I got an error as below
>>> [image: image.png]
>>> How can I fix this?
>>>
>>>
>>>
>>>
>>> 2023년 1월 3일 (화) 오전 4:05, Barry Smith <bsmith at petsc.dev>님이 작성:
>>>
>>>>
>>>>
>>>> On Jan 2, 2023, at 9:27 AM, 김성익 <ksi2443 at gmail.com> wrote:
>>>>
>>>> There are more questions.
>>>>
>>>> 1. Following your comments, but there is an error as below.
>>>> <image.png>
>>>> How can I fix this?
>>>>
>>>>
>>>> The previous value of PETSC_ARCH was not arch-main-debug do ls
>>>> $PETSC_DIR and locate the directory whose name begins with arch- that will
>>>> tell you the previous value used for PETSC_ARCH.
>>>>
>>>>
>>>> 2. After changing the optimized build, then how can I set the debug
>>>> mode again?
>>>>
>>>>
>>>> export PETSC_ARCH=arch- whatever the previous value was and then
>>>> recompile your code (note you do not need to recompile PETSc just your
>>>> executable).
>>>>
>>>>
>>>> 3.Following your comments, the new makefile is as below. Is it right?
>>>> CFLAGS = -O3
>>>> FFLAGS =
>>>> CPPFLAGS =
>>>> FPPFLAGS =
>>>> COPTFLAGS = -march=native
>>>>
>>>>
>>>> app : a1.o a2.o a3.o a4.o
>>>> $(LINK.C) -o $@ $^ $(LDLIBS)
>>>>
>>>>
>>>> include ${PETSC_DIR}/lib/petsc/conf/rules
>>>> include ${PETSC_DIR}/lib/petsc/conf/test
>>>>
>>>>
>>>> Best not to set these values in the makefile at all because they will
>>>> affect all compilers. Just set them with ./configure CCOPTFLAGS="-O3
>>>> -march=native"
>>>>
>>>>
>>>>
>>>> 4. I have no such processors. Where can I find benchmark information
>>>> about STREAMS?
>>>>
>>>>
>>>> do make mpistreams in PETSC_DIR
>>>>
>>>>
>>>>
>>>>
>>>> Thanks,
>>>> Hyung Kim
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> 2023년 1월 2일 (월) 오후 11:03, Matthew Knepley <knepley at gmail.com>님이 작성:
>>>>
>>>>> On Mon, Jan 2, 2023 at 4:16 AM 김성익 <ksi2443 at gmail.com> wrote:
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> Happy new year!!
>>>>>>
>>>>>>
>>>>>> I have some questions about “Hint for performance tuning” in user
>>>>>> guide of petsc.
>>>>>>
>>>>>>
>>>>>> 1. In the “Performance Pitfalls and Advice” section, there are 2
>>>>>> modes “debug” and “optimized builds. My current setup is debug mode. So I
>>>>>> want to change for test the performance the optimized build mode. However,
>>>>>> if I configure again, does the existing debug mode disappear? Is there any
>>>>>> way to coexist the 2 modes and use them in the run the application?
>>>>>>
>>>>> Suppose your current arch is named "arch-main-debug". Then you can
>>>>> make an optimized version using
>>>>>
>>>>> cd $PETSC_DIR
>>>>> ./arch-main-debug/lib/petsc/conf/reconfigure-arch-main-debug.py
>>>>> --with-debugging=0 --PETSC_ARCH=arch-main-opt
>>>>>
>>>>>
>>>>>> 2. In the guide, there are some paragraphs about optimization
>>>>>> level of compiler. To control the optimization level of compiler, I put the
>>>>>> ‘-O3’ as below. Is this right??
>>>>>> CFLAGS = -O3
>>>>>> FFLAGS =
>>>>>> CPPFLAGS =
>>>>>> FPPFLAGS =
>>>>>>
>>>>>>
>>>>>> app : a1.o a2.o a3.o a4.o
>>>>>> $(LINK.C) -o $@ $^ $(LDLIBS)
>>>>>>
>>>>>>
>>>>>> include ${PETSC_DIR}/lib/petsc/conf/rules
>>>>>> include ${PETSC_DIR}/lib/petsc/conf/test
>>>>>>
>>>>>
>>>>> You could dp this, but that only changes it for that directory. It is
>>>>> best to do it by reconfiguring.
>>>>>
>>>>>
>>>>>> 3. In the guide, user should put ‘-march=native’ for using AVX2
>>>>>> or AVX-512. Where should I put the ‘-march=native’ for using AVX?
>>>>>>
>>>>> You can add --COPTFLAGS="<user flags>" with any flags you want to the
>>>>> configure.
>>>>>
>>>>> 4. After read the “Hint for performance tuning” I understood that
>>>>>> for good performance and scalability user should use the multiple node and
>>>>>> multiple socket . However, before composing cluster system, many users just
>>>>>> can use desktop system.
>>>>>> In that case, between intel 13th i9 and amd ryzen 7950x, can the
>>>>>> 7950x, which has an arichitecture similar to the server processor, be more
>>>>>> suitable for petsc? (Because the architecture of intel desktop cpu is
>>>>>> big.little.)
>>>>>>
>>>>>
>>>>> A good guide is to run the STREAMS benchmark on the processor. PETSc
>>>>> performance closely tracks that.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Matt
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Hyung Kim
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> What most experimenters take for granted before they begin their
>>>>> experiments is infinitely more interesting than any results to which their
>>>>> experiments lead.
>>>>> -- Norbert Wiener
>>>>>
>>>>> https://www.cse.buffalo.edu/~knepley/
>>>>> <http://www.cse.buffalo.edu/~knepley/>
>>>>>
>>>>
>>>>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>
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