[petsc-users] Question - about the 'Hint for performance tuning'
Matthew Knepley
knepley at gmail.com
Tue Jan 3 06:45:56 CST 2023
On Tue, Jan 3, 2023 at 7:22 AM 김성익 <ksi2443 at gmail.com> wrote:
>
>
> 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.
>
No, I did not say that. Here is the quote:
Suppose your current arch is named "arch-main-debug".
But your arch was not arch-imain-debug. Instead it was arch-linux-c-debug,
which you used.
[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.
>
Your build is saying that the library does not exist. After configuration,
did you build the library?
cd $PETSC_DIR
PETSC_ARCH=arch-linux-c-opt make all
> [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.
>
If significant time is spent in your code rather than PETSc, it is possible.
>
>>
>>>
>>> 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?
>
https://www.cs.virginia.edu/stream/
Thanks,
Matt
> 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/>
>>
>
--
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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