[MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations

Yohei Takano - BAS yokano at bas.ac.uk
Mon May 13 10:16:55 EDT 2024


Hi Martin,

Thank you for following up on this, so it is not the xx_* files prep issue but something different.
I will try obtaining more information and see if I can trace the lines, and I believe the character length is good...

Regards,

Yohei
________________________________
From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
Sent: 13 May 2024 13:45
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations

the xx_* files in the zeroth iteration are generated and initialised as zeros by the model, no need to specify them.

Martin

On 13. May 2024, at 14:40, Yohei Takano - BAS <yokano at bas.ac.uk> wrote:

Hi Martin,

Thank you for clarifying and I agree, need to trave the line for #2  0x0000000000519133 in ctrl_map_genarr2d_ad_ ()
(which requires debug mode (devel) from my understanding, figuring out the other issue on this now).

I was tracing the forward/adjoint code found the fnamegenIn (e.g "fnamegenIn is xx_*.$iter.data, so the required access records starts at")
and for example for tauu, I have xx_ files, like "xx_tauu.effective.0000000000.data". The character length is not 80 but it is updated ones
with MAX_LEN_FNAME and it's 512 as in current code.

I might ask before but do we need to prepare xx_* files before running the adjoint sensitivity simulations? I think the codes generates it when
not provided so we thought it is okay...

Regards,

Yohei




________________________________
From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
Sent: 13 May 2024 13:08
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations

Hi Yohei,

I think you need to find out what the hex-code in this line of your traceback mean (i.e. which line):

#2  0x0000000000519133 in ctrl_map_genarr2d_ad_ ()

The error message is pretty clear, and since the last MITgcm routine is the taf-generated ctrl_map_genarr2d_ad, it should happen somewhere in that routine. But since this routine depends on your setup (CPP-flags, etc), it’s hard to see from here, where this should happen. In the forward code there are write statements like:

>       WRITE(fnamegenIn,'(2A,I10.10)')
>      & ctrlDir(1:ilDir)//fnamebase(1:ilgen),'.',optimcycle
>       WRITE(fnamegenOut,'(2A,I10.10)')
>      & ctrlDir(1:ilDir)//fnamebase(1:ilgen),'.effective.',optimcycle

which also appear in the ad-code, so I guess this is where it happens. What are the lengths of your “fnamegenin/out”? In current code they are “max_len_fnam” = 512, but I remember that we just changed that recently from 80.

Martin

> On 11. May 2024, at 16:55, Yohei Takano - BAS <yokano at bas.ac.uk> wrote:
>
> Hello everyone,
>
>    I followed Martin's suggestion commenting out the STRING part, but the error (core dump) still exists
> although the error slightly changed in core backtrace.
>
> -----
> #0  0x0000153e0f8793be in __cray_memcpy_ROME () from /opt/cray/pe/cce/15.0.0/cce/x86_64/lib/libu.so.1
> #1  0x0000153e0f88700e in __cray_memmove_ROME () from /opt/cray/pe/cce/15.0.0/cce/x86_64/lib/libu.so.1
> #2  0x0000000000519133 in ctrl_map_genarr2d_ad_ ()
> #3  0x000000000050a0c0 in ctrl_map_ini_genarr_ad_ ()
> #4  0x0000000000505f4e in ctrl_init_variables_ad_ ()
> #5  0x000000000068c07f in packages_init_variables_ad_ ()
> #6  0x000000000042ca7f in initialise_varia_ad_ ()
> #7  0x000000000041e819 in adthe_main_loop_ ()
> #8  0x0000000000a2c303 in the_model_main_ ()
> #9  0x0000000000978dc0 in main_ ()
> -----
>
>   I tried with debug mode (-devel) but I am having other issue with this on the HPC I am using (Archer2),
> turns out MITgcm is trying to write into a string and is writing too many characters, given the declared length of the string.
> I couldn't trace where this comes from yet (talking to my colleague, he said it could be anywhere...) but now I am a bit stuck.
>
> -----
> lib-4211 : UNRECOVERABLE library error
>   A WRITE operation tried to write a record that was too long.
>
> Encountered during a sequential formatted WRITE to an internal file (character variable)
> -----
>
>    For now, I will try with more stable (solid) adjoint setup and see if the adjoint simulations stably run on the HPC.
> My colleague suggested to try simpler adjoint setup in verification such as below so I will start and try from this setup again.
> https://github.com/MITgcm/MITgcm/tree/master/verification/tutorial_tracer_adjsens
> (I see this has been updated until recent but perhaps Martin can follow up on this).
>
>    Thank you for the suggestion and I will keep updated when something progresses.
>
> Regards,
>
> Yohei
>
>
> From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Yohei Takano - BAS <yokano at bas.ac.uk>
> Sent: 10 May 2024 14:18
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations
>  Thank you again for your continuous support Martin. I think I managed to finally trace the routine; I will check how things
> are working now.
>
> Regards,
>
> YoheiFrom: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
> Sent: 10 May 2024 13:17
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations
>  based on your backtrace message, your code will have a routine “ctrl_map_genarr2d_ad” somewhere (because it appears in the backtrace message). “grep” is your friend:
>
> cd build
> grep -i ctrl_map_genarr2d_ad *_ad.f
>
> Martin
>
> > On 10. May 2024, at 05:30, Yohei Takano - BAS <yokano at bas.ac.uk> wrote:
> >
> > Hi Matin, all,
> >
> >    Sorry again, I followed up and checked the adjoint code but turns out "ctrl_map_genarr2d_ad.F" code does not exist
> > (after make adall) and something strange might be happenning... (more specifically I don't see the forward ctrl_map_genarr2d.F
> > code in checkpoint68r but instead I see "ctrl_map_genarr.F" but still the adjoint code (ctrl_map_genarr_ad.F) is not generated...
> >
> >    I am not sure why this happened (I checked the code and ctrl package is included).
> >
> > Best regards,
> >
> > YoheiFrom: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
> > Sent: 09 May 2024 19:56
> > To: MITgcm Support <mitgcm-support at mitgcm.org>
> > Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations
> >  Hi Yohei,
> >
> > Since this is in the AD-code produced by TAF (ctrl_map_genarr2d_ad.F), that’s where you need to put the print statements (in the corresponding subroutine, you’ll findi it in your build directory after run "make adall" (or "make adtaf”)
> >
> > Martin
> >
> >> On 9. May 2024, at 09:32, Yohei Takano - BAS <yokano at bas.ac.uk> wrote:
> >>
> >> Hi Martin,
> >>
> >> Thank you so much for the details, good to know where I can dig in related to the issue.
> >> In pkg/ctrl, I think I found the relevant part of the code (although the code/file name is now different from what you mentioned,
> >> because of update? ,... and I use checkpint68r). In ctrl_map_genarr.F  (instead of ctrl_map_genarr2d_ad.F), I found the relevant
> >> subroutine (CTRL_MAP_GENARR2D) and I think I can try adding some "print-hallo" statement to trace what is happening.
> >> (other thing I spotted is that suroutine CTRL_MAP_GENARR2D is no calling tauu or tauv in the code,  but I might have missed something,
> >> still digging the codes).
> >>
> >> I am now running with the debugging options turned on, hope I can obtain line numbers.
> >> I will also try commenting out the string comparison part (commenting this part will not impact the adjoint simulations... correct?).
> >>
> >> Best regards,
> >>
> >> Yohei
> >>
> >>
> >>
> >> From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
> >> Sent: 09 May 2024 13:17
> >> To: MITgcm Support <mitgcm-support at mitgcm.org>
> >> Subject: Re: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations
> >>  Hi Yohei,
> >>
> >> this is difficult to debug without access to your specific hpc computer. Segmentation fault usually means some memory violation (array boundaries, or in your case maybe the length of a string, because of the _f90_string_compare).
> >>
> >> It looks like it’s failing in the AD-part of initialising the ctrl variables, i.e. when the gradients are finally written to the adxx_tauu files (in this case).
> >> My favorite debugger is the primitive “print-hallo” debugger: I would add print statements just before the call of ctrl_map_genarr2d_ad(tauu,tauu_ad, …) in ctrl_map_ini_genarr_ad.f or even within ctrl_map_genarr2d_ad (which will give you a lot of output) to try to figure out what’s going on.
> >>
> >> You can also run it with debugging options turned on, then the backtrace should give you linenumbers instead of hex-code
> >>
> >> If it runs 1 out of 5 times, the problem is most likely related to your computer or the way your computer handles internal writes (again because of the _F90_STRING_COMPARE). There are few string comparisons in ctrl_map_genarr2d_ad like:
> >>
> >> >       do k2 = 1, maxctrlproc
> >> >         if (xx_genarr2d_preproc(k2,iarr) == 'noscaling') then
> >> >           doscaling =  .false.
> >> >         endif
> >> >         if (xx_genarr2d_preproc_c(k2,iarr) == 'log10ctrl') then
> >> >           dolog10ctrl =  .true.
> >> >           log10initval = xx_genarr2d_preproc_r(k2,iarr)
> >> >         endif
> >> >       end do
> >>
> >>
> >> maybe you can try commenting them out for a test?
> >>
> >> Martin
> >>
> >> > On 9. May 2024, at 07:09, Yohei Takano - BAS <yokano at bas.ac.uk> wrote:
> >> >
> >> > Hello again,
> >> >
> >> >    Following up on this topic, what I got from the core dump information is
> >> >
> >> > -----
> >> > (gdb) backtrace
> >> > #0  0x00001534138194ea in __memcmp_avx2_movbe () from /lib64/libc.so.6
> >> > #1  0x00001534143fed66 in _F90_STRING_COMPARE () from /opt/cray/pe/cce/15.0.0/cce/x86_64/lib/libfi.so.1
> >> > #2  0x0000000000519160 in ctrl_map_genarr2d_ad_ ()
> >> > #3  0x000000000050a0c0 in ctrl_map_ini_genarr_ad_ ()
> >> > #4  0x0000000000505f4e in ctrl_init_variables_ad_ ()
> >> > #5  0x000000000068c28f in packages_init_variables_ad_ ()
> >> > #6  0x000000000042ca7f in initialise_varia_ad_ ()
> >> > #7  0x000000000041e819 in adthe_main_loop_ ()
> >> > #8  0x0000000000a2c513 in the_model_main_ ()
> >> > #9  0x0000000000978fd0 in main_ ()
> >> > -----
> >> >
> >> >    and STDOUT stops at this point (stops at the same point every time I run the model).
> >> >
> >> > ...
> >> > (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: adxx_tauu.0000000000.data
> >> > (PID.TID 0000.0001)  MDS_WRITE_FIELD: it,rec,kS,kL,kH=       0   -42  15   1   1 file=adxx_tauu.0000000000
> >> > (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: adxx_tauu.effective.00000000
> >> > ...
> >> >
> >> >    I think it is related to data access issues but still not sure why it runs successfully from time to time.
> >> > I am not sure if this is related but, in this configuration, I don't provide 2d or 3d control files in advance (i.e. xx_tauu.*data, meta etc.)
> >> > since I heard this will be generated during the run (and okay for adjoint sensitivity experiments, please correct me if I am wrong).
> >> >
> >> >    Thank you again in advance, please let me know if you have thoughts (or encountered similar issues before).
> >> >
> >> > Best regards,
> >> >
> >> > Yohei
> >> >
> >> >
> >> > From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Yohei Takano - BAS <yokano at bas.ac.uk>
> >> > Sent: 07 May 2024 12:24
> >> > To: mitgcm-support at mitgcm.org <mitgcm-support at mitgcm.org>
> >> > Subject: [MITgcm-support] Segmentation Fault in MITgcm Adjoint Simulations
> >> >  Hello all,
> >> >
> >> >    My colleague and I have been working on adjoint sensitivity setup & simulations
> >> > based on global coarse resolution biogeochemistry model (https://github.com/MITgcm/MITgcm/tree/master/verification/tutorial_global_oce_biogeo),
> >> > similar configurations but we have our own customization.
> >> >
> >> >     We manage to compile the model and run adjoint test simulations. However, the model crashes
> >> > (with segmentation fault) towards the end of adjoint simulations and we would like your advice to
> >> > figure out why this is happening. The strange part is that we manage to successfully run at one point
> >> > but when try to reproduce with the exact same setting (on the same HPC) it starts to crash again...
> >> > Roughly speaking 1 out of 5 times it runs successfully but most of the time crashes at the same point.
> >> > We are puzzled because we are using the exact same settings/executable every time and wondering what causes
> >> > this unstable situation. The environment should be the same everytime we run the model.
> >> >
> >> >     Does anyone have similar experiences? Here is the code/configuration I have been working on with my colleague Dani Jones.
> >> > https://github.com/ytakano3/MITgcm_BGC_Model_Config
> >> >
> >> >    In "global_ocn3deg_bgcv0" you see "code_ad" and "input_ad/input_ad_kpp_atmco2pv0" and you can compile
> >> > (with TAF) and run the model. It is 2 years test run. When I am trying this, it fails (i.e. segmentation fault) most of the time but
> >> > again say 1 in 5 times the model runs successfully... We would like to figure out why this is happening, why it gets unstable so
> >> > let me know if you have thoughts on this.
> >> >
> >> >    Sorry about the long e-mail but please let me know if anything is unclear. Thank you in advance.
> >> >
> >> > Regards,
> >> >
> >> > Yohei
> >> >
> >> >
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> >> >
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