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Ideas for RPA Crash

  • verify VBIOS settings same as nvidia (yes)
  • try without "setenv CUDA_DEVICE_WAITS_ON_EXCEPTION 1" (still fails)
  • run crash_test.c at keeneland (fails there too)
  • change bios settings as recommended by colfax (still fails)
  • swap C2075 with M2090 (problem follows the M2090!)
  • remove IB card (still fails)
  • try random matrix data instead of fixed data (fails with random, works with fixed)
  • run colfax memory test
  • reduce power consumption with "nvidia-smi --perf-limit=P4" (also tried P9). (Fixes crashes, but still get corrupt data).
  • try 1 gpu per node, to see if gpus are "fighting", or if cooling/power is a problem (still fails)
  • look for particular set of gpus that fail
  • switch to cudamemcpy in crash_test.c
  • make matrix bigger in crash_test.c
  • run crash_test.c on 1 gpu per node (still fails)
  • compare suncat-gpu-test (doesn't fail) and suncat-gpu (fails):
    • C2075 vs. M2090
    • 7 vs. 8 gpus
    • IB card
    • cooling
    • power cables? (c13 vs. c19)
  • run nbody gpu test, as suggested by colfax (doesn't fail)
  • read gpu temps (read out via ipmi: code fails with temp around 69C (lower than C2075 where nvidia-smi reports 88C))
  • read rack temps (67-72 at inlet, 86-94 at outlet)
  • run crash_test.py with P9 (no failures)
  • run 32 gpu N-N with 3-gpus per node in exclusive mode (rack 1 still warm on the outputs: 88,88,92 (top to bottom on the front panel). Still saw nan's in dbgcrash_fast/try19.
  • run with rack doors open, or change rack cooling behavior
  • check that PyArgParseTuple types match between python/C
  • cuda4
  • check power
  • small c version of crash_test.py
  • look at ipmi errors on gpu24/26: nothing
  • look in /var/log/messages for errors from driver
  • security scans
  • run gpu hardware tests (with colfax software?)
  • gcc instead of icc
  • small file crash (yes, crashed after 2 days)
  • keeneland (saw 1 nan failure and 1 kernel launch failure)
  • simple gemm test crash
  • does it crash on 1 node? (yes on suncat-gpu 4 cores (gpu20, and gpu26), but not on suncat-gpu-test)
  • mpi errors?
  • try magma GEMM (still crashes)
  • eliminate IB fork warning (still crashes)
  • race condition between cublasDestroy/cublasCreate? (no, happens after first create)
  • study with valgrind (dbgcrash_fast/try11,13,14 show some uninitialized data in mpisum)
  • study with cuda-memcheck (see dbgcrash_fast/try12) looks clean for the 32-node job, even when the data gets messed up (see many warnings about python numerical overflows, indicating failure has occurred)
  • understand imprecise exceptions
  • run @nvidia with 8*M2090, Tyan motherboard, and cuda 5.0 (works!)
  • hardware problem (check for common node, too many jobs in the logfiles)
  • read the code: cudamemcpy memory overrun?
  • discontiguous numpy array? (put in asserts)
  • did get a memory error when running racecheck
  • no errors from cuda-memcheck heap check
  • read code to look for race conditions in cukernels.cu (even though problem existed before the addition of those kernels)
  • ran cuda-memcheck racecheck: only saw errors from cublas
  • check ecc enabled. looked with "nvidia-smi -q"
    Ecc Mode
    Current : Enabled
    Pending : Enabled

To-Do List

Nvidia GTC questions
  • what intermittent errors does cuda-memcheck not detect?
    • hardware
    • cudamemcpy
    • others?
  • cuda-gdb generates output for kernel launches. slows down the code dramatically? becomes unusable.
    • set flag "set cuda kernel_events 0"
    • submit bug report if not solved
  • how does cuda deal with memory fragmentation?
  • nvvp error: "102 metrics have invalid values due to inconsistencies in the required event values"
    • trying to match up the counters in time, if not well-synchronized gives the above error. Larger pages.
    • handled differently by nsight (replays previous profiler)
  • double complex math: really fp64 instructions?
    • only double-precision
  • talk to Gernot Ziegler about instruction limited kernels?
  • is our zherk kernel latency limited?
    • multiple of 8 for k (8 rows at time in the loop)
    • may be limited by pieces at the beginning/end (end: scaling by alpha, beta, beginning: load the shared memory) loop over k in the middle
    • kepler: k up to 1000 for top performance
  • cufftplanmany memory leak
  • trigger crash on nan? how do nan's get produced?
    • not possible to trigger a crash on nan
  • why do they use bytes-per-instruction
  • get many errors from cublas with race check
    • if really errors: submit bug report
  • if we have 1 number used by many threads should it go into shared memory? constant memory?
    • we would think constant memory would be the right answer. shared memory would give a bank conflict.
  • what memory access errors can memcheck detect? cudamemcpy? array-out-of-bounds?
    • doesn't detect cudamemcpy errors (or any errors by the host) but does detect array-out-of-bounds accesses within the GPU
  • we were not 16-byte aligning cuDoubleComplex variables. error showed up "much later" in cuGetVector (error 11) and cudaDeviceSynchronize (error 4). Did binary search to find source of error. How do we program error-checks so that run-time errors show up "immediately"? cuda_safe_call?
    • pattern for error checking: issue different kernels in different streams, then do cudastreamsynchronize and cudagetlasterror
  • understand crash with rpa-gpu-expt running rpa_only_Na_cuda.py with nvprof
    • should file a bug report
3/12/2013
  • look profiling on RPA (lin)
  • ask about error handling at GTC (lin)
  • base.py get_phi_agp kernel
  • rpa manuscript (jun)
  • k-point parallelization (cpo)
3/5/2013
  • 2 slides for Samuli
  • run profiling on RPA (lin)
  • memory leak (perhaps related to crashes)
  • adding error check functions
  • base.py get_phi_agp kernel
  • rpa (jun)
    • manuscript
2/26/2013
  • 2 slides for Samuli
  • more structs for RPA (lin)
  • run nvvp on RPA (lin)
  • think about EXX
  • rpa (jun)
    • manuscript
2/19/2013
  • more structs for RPA (lin)
  • commit code
  • rpa (jun)
    • keep on eye on crashes
  • EXX on GPUs
    • fix MPI stuff in EXX
    • understand why it doesn't speed up
    • think about whether or not we tackle EXX yet
2/12/2013
  • structs for RPA
  • rpa (jun)
    • keep on eye on crashes
    • EXX on GPUs
2/5/2013
  • profile GPU-GPAW with maxed out memory on the GPU (lin)
  • gpu-gpaw profiling thoughts:
    • cpo thinks improving mpi performance may be difficult
    • lin thinks improving mpi performance may be important, since number of k-points decreases in future.
    • maybe we could pipeline other work while mpi is running?
    • why do we only get a x5 speedup for Pt 3x3x4? (samuli sees 8 to 11)
  • see if the mask stuff is called every SCF step (aj)
  • think about randomization idea (aj)
  • evaluate effectiveness of tzp+PK on na2o4/pt (aj)
  • freeze D_aps?
  • rpa (jun)
    • keep on eye on crashes
    • rewrite code for the ZHERK
1/29/2013
  • profile GPU-GPAW in grid mode (lin)
  • gpu-gpaw profiling thoughts:
    • domain decomposition is especially inefficient on GPU: pack as much domain onto one GPU as possible (need larger memory)
    • parallelization over k-points remains good
    • our current 1-k-point on 8 cores is unrealistic for a 3x3x4
    • cpo thinks improving mpi performance may be difficult
    • lin thinks improving mpi performance may be important, since number of k-points decreases in future.
    • maybe we could pipeline other work while mpi is running?
    • why do we only get a x5 speedup for Pt 3x3x4? (samuli sees 8 to 11)
  • email the list about the real-density mixer (aj)
  • see if the mask stuff is applied every SCF step (aj)
  • think about randomization idea (aj)
  • evaluate effective of tzp+PK (aj)
  • rpa (jun)
    • keep on eye on crashes
    • rewrite code for the ZHERK
1/22/2013
  • libxc on gpu (lin)
    • work on automake stuff on Thursday
    • ping Miguel
  • AJ tries simple new-setup Pt system with rmm-diis
    • use same code with different setups or vice-versa
    • generate residual compared to converged
  • cpo compares FFTMixer to dacapo
  • rpa (jun)
    • merge trunk and print pointers to understand crashes
    • rewrite code for the ZHERK
Questions for Nvidia
  • how to use constants memory
    • constants memory: broadcast same 4 bytes to all threads of a warp, if the request is synchronized. a performance penalty if they don't. must explicitly call it out with _constant_ (for kepler "immediates" are stored in the constants memory if large enough, otherwise instruction).
  • how to use texture memory
    • textures: if used in a "2D or 3D" manner, can only store 4 bytes. in kepler: can use ldg. memory has been ordered in a strange way ("snake") to allow better accesses to multi-dimensional stuff. ugly with double precision, because of the 4-byte size.
  • what does the 150GB/s mem bandwidth number mean?
    • it is sum of read/write bandwidth (each is 75GB/s)
  • optimization tricks: pre-fetch etc.
    • we get 85GB/s out of 150GB/s on 2075. use cudaDMA?
    • philippe measures 84% memory bandwidth (154GB/s) on K20
  • what does a queued warp do? (does it pre-fetch the memory)
    • yes, but can do better (e.g. cudaDMA)
  • reducing number of registers in kernel (does compiler typically do this optimally?)
    • can control register usage using launch bounds
  • how to learn with nvvp if we're memory/flops limited
    • philippe just counts instructions and measures MB/s by running code (no NVVP). He has some special code that counts instructions for him in complicated cases.
  • understanding the nvvp columns
    • ECC decreases memory performance 20%. (118GB/s for 2075)
    • 106GB/s is "quite good"
    • 90% is the highest
    • maybe we should turn off ECC? Will lose statistics.
      Code Block
      dynamic shared memory:  extra launch parameters: stream and amount of shared memory to allocate dynamically 
instruction replay overhead: 
  "sum" (different columns have different denominators) of next 3 columns: 
  o can replay because needed to fetch multiple cache lines per global memory access instruction  (e.g. because of cache-line misalignment) 
  o can replay because needed to fetch multiple cache lines per local memory access instruction (NOTE: this is "LOCAL MEMORY CACHE REPLAY OVERHEAD") 
  o shared memory bank conflict 
global memory store efficiency:  measure of stored bytes vs. "real" stored bytes (should only be <100% if we have cache-line misalignments) 
local memory overhead: measures local memory accesses (stack traffic, register spill traffic) 
warp execution efficiency:  measure of branch-divergence (percentage of threads that are active in a warp) 
global memory load efficiency:  measure of loaded bytes vs. "real" loaded bytes (should only be <100% if we have cache-line misalignments) 
achieved occupancy: this is from "tail" from the numerology of number of waves of blocks 
instructions issued: number of warps instructions issed to all SMs.  compare to 1.15GHz*#SMs*duration (maximum of 1) 

NOTe internally fermi: really runs 2 half-warps over 2 clocks, but the above math still works out for the simple-minded. 
 
NOTE: executed: first time , issued: includes replays
  • best way to associate right GPU with right core (e.g. "taskset", "numactl")
    • if numactl settings OK, OS should take care of that. still have to correct taskset/cuCreate
  • ask about zher speedup numbers: for 4kx4k why does gemm improve by x30 but zher improves by x6?
    • gemm with large sizes is compute limited, which GPU does well. zher is memory limited.
  • using automake with cuda and c in one library?
    • no good answer
  • nvidia-proxy allocation: free up memory?
    • proxy doesn't provide a good way to free up memory
1/8/2013
  • libxc on gpu (lin)
    • work on automake stuff
    • get the cleaned-up ifdef version from Miguel
  • digest RPA timing measurements (lin)
  • AJ tries simple new-setup Ru system with rmm-diis
    • generate temperature residual plot
    • generate residual compared to converged
  • cpo compares FFTMixer to dacapo
  • paper (jun)
  • redo timing measurements (jun/lin)
  • understand new GPU box memory slowness (cpo)
12/18/2012
  • libxc on gpu (lin)
    • use common work file for CPU/GPU
  • digest RPA timing measurements (lin)
  • paper (jun)
  • redo timing measurements (jun)
  • understand timing measurements more fully (jun)
  • dacapo density mixing vs. GPAW (cpo)
12/11/2012
  • understand nvidia zgemm speedup plot (jun/cpo)
    • ANSWER: without thread: 29 faster on GPU. With 6 thread openMP get 5, which agrees with nvidia
  • understand why zher is x6 better on GPU but we see x24 with RPA (will put device sync in code) (jun/cpo)
    • ANSWER: CPU is memory bandwidth limited (so faster with 1 core). account for roughly x2, and the other x2 comes from overlapping CPU/GPU computation.
  • does cuda5 improve ZHER? (jun/cpo) ANSWER: no improvement
  • libxc on gpu (lin)
    • use common work file for CPU/GPU
  • digest RPA timing measurements (lin)
  • think about moving lambda calc to GPU (jun) (ANSWER: no need, 10 or 20% improvement, best case)
  • try multiple surfaces with jacapo/gpaw-pw (aj)
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • make sure all libxc self-tests run
  • why doesn't marcin's na.py converge, even with fixed density?
  • can the alphas for the nt_G really be used for the D's?
12/4/2012
  • understand nvidia zher speedup plot (jun/cpo)
  • libxc on gpu (lin)
    • use CUDA5
    • use common functional file for CPU/GPU
    • use common work file for CPU/GPU
    • read samuli old talk
    • run 3x4x3 pt system
  • RPA timing measurements (lin)
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • try multiple surfaces with jacapo/gpaw-pw (aj)
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
  • make sure all libxc self-tests run
  • move suncatgpu01 to CUDA5 (cpo)
11/27/2012
  • come up with list of items to ask about at nvidia mtgs
  • libxc on gpu (lin)
    • read samuli old talk
    • run 3x4x3 pt system
    • run PBE0
    • fix linking undefined symbol
    • make sure all self-tests run
    • put paramsize fix in for mgga and lda
    • test libxc 2.0.0
  • RPA timing measurements (lin)
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • try multiple surfaces with jacapo/gpaw-pw (aj)
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
  • "patch" file for libxc (only the memsets?) (cpo)
  • move suncatgpu01 to CUDA5 (cpo)
  • figure out how to softlink lda_c_pw.cuh (cpo)
11/20/2012
  • libxc on gpu (lin)
    • fix the zeroing (is there a cudamemset?)
    • make sure all self-tests run
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • try multiple surfaces with jacapo/gpaw-pw (aj)
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
  • merge libxc-gpu and libxc (patch memsets, and zero-ing in work) (cpo)
  • "patch" file for libxc (only the memsets?) (cpo)
  • move suncatgpu01 to CUDA5 (cpo)
11/13/2012
  • libxc on gpu (lin)
    • fix the zeroing (is there a cudamemset?)
    • double check timing for LCAO results
    • make sure all self-tests run
    • commit to svn
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
  • merge libxc-gpu and libxc (patch memsets, and zero-ing in work) (cpo)
11/6/2012
  • libxc on gpu (lin)
    • decide what to do about the hacks (with print statements)
    • copy less of the scratch data to GPU
    • run the self-tests
    • see if performance is better/worse
    • check that unmodified libxc still works
    • commit to svn
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
  • merge libxc-gpu and libxc (patch memsets, and zero-ing in work) (cpo)
10/30/2012
  • libxc on gpu (lin)
    • remove print statements
    • merge libxc-gpu and libxc
    • copy less of the scratch data to GPU
    • run the self-tests
    • do the memsets for lda/mgga
    • see if performance is better/worse
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • install GPAW on Keeneland (cpo)
10/23/2012
  • libxc on gpu (lin)
    • remove print statements
    • test spin-polarized
    • understand why H numbers are different than gpugpaw_v2
    • merge libxc-gpu and libxc
  • multi-alpha zher at a lower priority(jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • try calling dacapo density mixing from GPAW (cpo)
  • get journal recommendations from Nichols (cpo)
10/4/2012
  • libxc on gpu (lin)
    • PBEsol-X
    • put libxc in samuli branch at "low-level" (libxc.py?)
    • solve zero-ing problem and stride problem
  • multi-alpha zher (jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • try calling dacapo density mixing from GPAW (cpo)
9/25/2012
  • libxc on gpu (lin)
    • test PBEsol
    • cleanup existing code (delete commented lines, unused code)
    • put in p_d_gga an p_d_mgga, for consistency
    • have 1 beautiful program that runs a lda/gga/mgga functional on both CPU/GPU and times them.
    • think about integrating with samuli
  • multi-alpha zher (jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • work on understanding jacapo density mixing
9/18/2012
  • libxc on gpu (lin)
    • focus on tpss_x (summarize pattern for moving functional to gpu)
    • ask samuli if there are functionals he would like us to move?
    • figure out how to get nested param-size (will change "p" struct for this, in general it would be a function to deep-copy params)
    • figure out how to get p_d into the functional (will change "p" struct for this)
    • kinetic functionals
    • understand PBE instruction replays and constants-memory
    • think about cleanup of p
    • summarize pattern for moving functional to gpu
    • better pattern for p_d?
    • think about integrating with samuli
  • multi-alpha zher (jun)
    • reduce registers? prefetch?
    • explore the parameter space: tile-size
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • work on understanding jacapo density mixing
9/5/2012 and 9/12/2012
  • libxc on gpu (lin)
    • do mgga (summarize pattern for moving functional to gpu)
    • figure out how to get nested param-size (will change "p" struct for this, in general it would be a function to deep-copy params)
    • figure out how to get p_d into the functional (will change "p" struct for this)
    • kinetic functionals
    • understand PBE instruction replays and constants-memory
    • think about cleanup of p
    • summarize pattern for moving functional to gpu
    • better pattern for p_d?
    • think about integrating with samuli
  • multi-alpha zher (jun)
    • run nvvp
    • look at occupancy calculator (get registers from nvvp)
    • think of new ideas to speed-up
    • explore the parameter space: threads-per-block, tile-size
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • work on understanding jacapo density mixing
8/28/2012
  • libxc on gpu (lin)
    • do mgga (summarize pattern for moving functional to gpu)
    • figure out how to get nested param-size (will change "p" struct for this, in general it would be a function to deep-copy params)
    • figure out how to get p_d into the functional (will change "p" struct for this)
    • kinetic functionals
    • understand PBE instruction replays and constants-memory
    • think about cleanup of p
    • summarize pattern for moving functional to gnu
    • better pattern for p_d?
    • think about integrating with samuli
  • multi-alpha zher (jun)
    • understand current code
    • understand nvidia suggestions
  • fix timing of cublas vs. source-code zher and run benchmark
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • work on understanding jacapo density mixing
8/21/2012
  • libxc on gpu (lin)
    • performance plot for RPBE (lin)
    • do mgga (summarize pattern for moving functional to gpu)
    • understand crash for large number of grid points
    • figure out how to get nested param-size (will change "p" struct for this, in general it would be a function to deep-copy params)
    • figure out how to get p_d into the functional (will change "p" struct for this)
    • read thru func_aux
    • kinetic functionals
    • time PBE
    • look at nvvp to understand bottleneck
    • think about cleanup of p
    • summarize pattern for moving functional to gnu
    • better pattern for p_d?
    • think about integrating with samuli
  • multi-alpha zher (jun)
  • paper (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • add Na2O4 calculation to AJ infrastructure
    • understand default jacapo/gpaw parameters/algorithms/initial-values
8/15/2012
  • libxc on gpu (lin)
    • performance plot for RPBE (lin)
    • work on either the mgga or the copying of "p"
    • understand crash for large number of grid points
    • read thru fund_aux
    • time PBE
    • look at nvvp to understand bottleneck
    • think about cleanup of p
    • summarize pattern for moving functional to gnu
    • better pattern for p_d?
  • evaluate possible gpu purchase (jun)
  • multi-alpha zher (jun)
  • paper and speeding up more (FFT?) (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • add Na2O4 calculation to AJ infrastructure
    • understand default jacapo/gpaw parameters/algorithms/initial-values
8/8/2012
  • libxc on gpu (lin)
    • performance plot for RPBE (lin)
    • work on either the mgga or the copying of "p"
  • evaluate possible gpu purchase (jun)
  • multi-alpha zher (jun)
  • paper and speeding up more (FFT?) (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • add Na2O4 calculation to AJ infrastructure
    • understand default jacapo/gpaw parameters/algorithms/initial-values
7/11/2012
  • libxc on gpu (lin)
  • evaluate possible gpu purchase (jun)
  • multi-alpha zher (jun)
  • create infrastructure for running convergence tests (aj)
  • help with all the above (cpo)
    • add Na2O4 calculation to AJ infrastructure
    • understand default jacapo/gpaw parameters/algorithms/initial-values
6/27/2012
  • libxc on gpu (lin)
  • more convergence test cases (aj)
  • think about FFT cutoff (aj)
  • xsede machines
    • generate benchmark strong-scaling plots for exx/rpa for forge (jun)
    • create proposal rough draft (jun)
  • finish libxc (cpo)
6/20/2012
  • libxc on gpu (lin)
  • more convergence test cases (aj)
  • think about FFT cutoff (aj)
  • xsede machines
    • install software on forge (cpo)
    • generate benchmark strong-scaling plots for exx/rpa for gordon/forge (no swapping!) (jun)
  • finish libxc (cpo)
6/13/2012
  • libxc on gpu (lin)
  • more convergence test cases (aj)
  • think about FFT cutoff (aj)
  • xsede machines
    • install software on forge (cpo)
    • understand gordon error (cpo)
    • generate benchmark strong-scaling plots for exx/rpa for forge (no swapping!) (jun)
  • finish libxc (cpo)
6/13/2012
  • try libxc on gpu (lin)
  • more convergence test cases (aj)
  • think about FFT cutoff (aj)
  • see if we get 50% speedup with new zher code (jun)
  • xsede machines
    • install software (jun/cpo)
    • generate benchmark strong-scaling plots for exx/rpa for forge (no swapping!) (jun)
  • work on libxc (cpo)
5/30/2012
  • understand x/c kernel bottleneck with nvvp (lin)
  • trying cufft to see what we gain (lin)
  • more convergence test cases (aj)
  • think about FFT cutoff (aj)
  • GEAM, ZHERK (jun)
  • xsede machines (jun/cpo)
    • generate benchmark strong-scaling plots for exx/rpa (no swapping!)
    • use std err to look for node-to-node "time variations"
  • work on libxc (cpo)
5/23/2012
  • understand x/c kernel bottleneck with nvvp (lin)
  • trying cufft to see what we gain (lin)
  • use VO as convergence test case (aj)
  • look at special-metric-weight convergence (aj)
  • think about FFT cutoff (aj)
  • GEAM, ZHERK (jun)
  • build on hopper and xsede machines (jun/cpo)
    • generate benchmark strong-scaling plots for exx/rpa (no swapping!)
    • use std err to look for node-to-node "time variations"
  • work on libxc (cpo)
5/9/2012
  • rpbe kernel (lin)
    • does memcpyasync need cudamallochost?
    • fix stream behavior and try with 1,2,4,8,16 streams
    • understand stream behaviour with nvvp
  • zher streams(jun)
    • in benchmark, have separately variable nstream/nw
    • can we see whether we have 4 or 16 streams?
    • understand stream behaviour with nvvp
  • density mixing (aj)
  • work on libxc (cpo)
5/2/2012
  • looking at EXX bottleneck (rewriting) (jun)
  • use cuda streams for small RPA systems (jun)
  • libxc integration (cpo)
  • understand MKL benchmark (jun/cpo)
  • pycuda (cpo)
  • understand RPBE kernel: (lin)
    • understand "double" problem
    • vary np, block_size, nstreams
    • loop testfunc many times
    • longer term: look at jussi/samuli kernel for ideas
4/25/2012
  • looking at EXX bottleneck (rewriting) (jun)
  • postpone work on ZHER stuff until we have news from INCITE (jun)
  • talk to Frank about computing time applications (cpo)
  • understand MKL benchmark (jun/cpo)
  • libxc integration (cpo)
4/18/2012
  • look at reduced-scope libxc example plus RPBE (lin)
  • if there is time, benchmark the RPBE kernel (lin)
  • zher performance improvement with multiple streams (jun)
  • make INCITE version work (jun/cpo)
  • move to libxc 1.2 (cpo)
4/11/2012
  • libxc parallelization (lin)
  • libxc integration (cpo)
  • understand missing time in cublas mode (jun/cpo)
  • how to put the gemm in PW mode in a fairly neat way (lin/cpo)
  • start working on multiple-alpha kernel (MAZHER) (jun/cpo)
  • work on INCITE proposal (jun/cpo)
3/28/2012
  • gemm (lin)
  • run pt3x3 (cpo)
  • libxc (cpo, and lin if he finishes gemm)
  • cher/fft (jun)
  • fix gpu allocation (cpo)
  • circular dependency problem with monkhorst_pack (cpo)
  • mpi failure with cuzher (cpo)
3/21/2012
  • batch queue for GPU machine (cpo)
  • fft/gemm/gemv (lin/jun/cpo)
  • single precision cher instead of zher? (jun/cpo)
  • new libxc (cpo)
  • fix libfftw detection (cpo)
  • improve zher in cuda (long project, jun/cpo)
  • move "expand" from python into C, post to mailing list? (lin)
  • look at spin paired (cpo)
  • run pt3x3 (cpo)
3/14/2012
  • pycuda compatibility (cpo)
  • private svn (cpo)
  • try nvvp/transpose (or C60 with more grid points) for >5 minutes (lin)
  • send mail to nvidia or list to understand why nvvp profile cuts off after 5 minutes (lin)
  • understand bottleneck in get_wfs (jun)
  • implement fft/gemv (cpo)
  • is there a cuda library for trace like zgeev (cpo)
  • run a 3x3x3 system to see if bottlenecks stay the same (cpo)
  • driver hang status (cpo)
  • understand how to fix gs.py bottlenecks in more detail (lin/cpo) using gpaw profiler:
    • pseudo density: density.py: self.calculate_pseudo_density(wfs) (cpo)
    • projections: overlap.py: wfs.pt.integrate(psit_nG, P_ani, kpt.q) (cpo)
    • RMM-DIIS: eigensolvers/rmm_diis.py: lots of lines (cpo)
    • projections: eigensolvers/rmm_diis.py: wfs.pt.integrate(dpsit_xG, P_axi, kpt.q) (lin)
    • calc_h_matrix: eigensolvers/eigensolver.py: H_nn = self.operator.calculate_matrix_elements, hamiltonian.xc.correct_hamiltonian_matrix (lin)
    • rotate_psi: eigensolvers/eigensolver.py (lin)

Accessing suncatgpu01 SVN

We have put a version of GPAW in a local SVN repository on suncatgpu01. To access it, use the following:

Code Block
svn co svn://localhost svngpaw

You can put whatever you want for the last argument (local directory name).

General Topics

  • Stanford CUDA course: http://code.google.com/p/stanford-cs193g-sp2010/
  • (Everyone) Understand gpaw (read paper)
    • what other steps could we parallelize?
    • Can we do existing parallelization better? (e.g. use ideas in Todd's GPU papers)
  • (Everyone) Go through CUDA tutorial here.
    • Understand blocks/threads/warps and how they map onto GPU hardware (details of which can be seen with "deviceQuery" command)
  • (Lin) Find tool to measure:
    • memory bandwidth usage
    • gpu flops usage
  • (Jun) :
    • Parallelize LCAO/planewave/RPA (zher performance?)? non-rmm-diis eigensolver?
    • merge with trunk?
  • (cpo) :
    • Understand code flow
    • Understand where the ~23 cuda kernels are used
    • Understand which bottlenecks we need to tackle
  • Do another gpu-gpaw install (to learn)
  • Understand Pt 3x4x3 CPU/GPU difference versus 3x2x3 (performance scaling with system size)
  • Can multiple CPU processes win by using the same GPU?
  • Understand pycuda
  • Understand gpaw interface to cuda (c/cuda subdirectory)
  • Read CUDA programming manual here.
  • Do all gpaw self-tests pass with GPUs?
  • Can we get bigger bang-per-buck with GeForce instead of Tesla? (don’t need GPUDirect, maybe live with less memory/bandwidth? double precision worse)
  • Understand cuda better:
    • Does Samuli use pinned memory correctly?
    • run/understand cuda a bandwidth benchmark
    • Could we use GPUdirect for MPI data transfer?
  • Does the GPU performance scale with the product of gridpoints*bands? Might be a combinatorial effect with the bands, linear with the grid points?
  • Duplicate Samuli results
  • Update to most recent version in svn
  • Understand where gpaw scaling maxes out for Pt 3x4x3
  • Why is CO on 2 GPUs slower than on 8 CPUs?
  • Can we do something less precise in the vacuum area? (fewer grid points?)
  • Do we need a fatter interconnect for GPUs?