2020-08-28

For some reason mem_23344 is not in inuse_outside in statement x_22902.

Tomorrow, I need to figure out why.

I guess the problem is that the LastUse analysis reports mem_23344 as being last-used in the lw_dest_23227 statement. Why isn't the use in statement res_22622 being picked up? Ah, no, it's actually also reported as last-used in res_22622:

stm: lw_dest_23227
inuse0: [inpacc_mem_23491, acc0_mem_23496]
inuse_outside: [mem_23344, inpacc_mem_23491, acc0_mem_23496]
new_mems0: [[num_und_22442][num_dates_22444]f32 lw_dest_23227]
new_mems1: [mem_23344]
new_mems: [mem_23344]
meminfo: [, mem_23344,]
last_use_mems: [mem_23344]

stm: res_22622
inuse0: [mem_23344, inpacc_mem_23491, acc0_mem_23496, mem_23517]
inuse_outside: [mem_23344, inpacc_mem_23491, acc0_mem_23496, mem_23517]
new_mems0: [[num_und_22442][num_dates_22444]f32 res_22622]
new_mems1: [mem_23344]
new_mems: [mem_23344]
meminfo: [mem_23344]
last_use_mems: [mem_23344]

Aha, result_23224 is being reported as last-used in statement res_22622. That's true, but the last-use of mem_23344 that implies should be offset by the use of it in res_22622.

I think the problem was that I was uncritically accepting all last-uses from inside an expression. I needed to make sure that all new memory blocks in a statement are always in use after that statement. Here is the fix.

Now, it seems like OptionPricing.fut is actually compiling and testing successfully! I've now compiled my version of Futhark on gpu04, and am about to try running all tests.

Only three errors!

$ futhark test --backend=opencl --exclude=no_opencl tests/
tests/issue708.fut:
Compiling with --backend=opencl:
Internal compiler error.
Please report this at https://github.com/diku-dk/futhark/issues.
Type error after pass 'reuse allocations':
In function main
When checking function body
In expression of statement {i32 size_5333, i32 size_5334, i32 res_ixfn_5707, i32 res_ixfn_5708,
 i32 res_ixfn_5711, i32 res_ixfn_5712, i32 res_ixfn_5714, mem res_mem_5717;
 [size_5333][size_5334][3i32]i8 res_5335}
Inside the loop body
In expression of statement {[loop₃_5337][loop₄_5338][list_insertions_arg_5332][3i32]i8 res_5623}
In expression of statement {mem color_5726}
In subexp bytes_5685
Use of unknown variable bytes_5685.

tests/issue1025.fut:
Compiling with --backend=opencl:
Warning at tests/issue1025.fut:25:11-13:
  Unused variable "xp0".

Warning at tests/issue1025.fut:25:18-20:
  Unused variable "yp0".

Warning at tests/issue1025.fut:28:1-81:12:
  Entry point parameter

    (rects: [n₅₉]({x: i32, y: i32}, {x: i32, y: i32}))

  will have an opaque type, so the entry point will likely not be callable.
Internal compiler error.
Please report this at https://github.com/diku-dk/futhark/issues.
Type error after pass 'reuse allocations':
In function main
When checking function body
In expression of statement {mem res_mem_9435;
 [n₅₉_8016][lifted_0_rect_pixel_indices_arg_8050]bool res_8056}
In expression of statement {[n₅₉_8016][lifted_0_rect_pixel_indices_arg_8050]bool res_8398}
In expression of statement {i64 maxSubHelper_9441}
In subexp bytes_9146
Use of unknown variable bytes_9146.

┌──────────┬────────┬────────┬───────────┐
│          │ passed │ failed │ remaining │
├──────────┼────────┼────────┼───────────┤
│ programs │ 1449   │ 2      │ 0/1451    │
├──────────┼────────┼────────┼───────────┤
│ runs     │ 2556   │ 2      │ 0/2558    │
└──────────┴────────┴────────┴───────────┘
 (3 program(s) excluded).

Troels suggested attending the Supercomputing conference, or at least look in to some of the workshops.

This is what he's talking about. It doesn't look expensive.

Here are some interesting tutorials:

• How to program AMD GPU devices with HIP: from writing new applications to porting existing CUDA code
• Better Scientific Software
• Parallel Computing 101 - Part 1, although it may be a bit too basic.
• Performance Tuning with the Roofline Model on GPUs and CPUs: Part 1

Perhaps there are also some interesting workshops.

Today I learned that weechat has a sophisticated relay system, that allows you to connect to a running weechat instance from another client. For instance, by following the instructions on Glowing Bear, I was able to connect to my weechat instance on munksgaard.me from the Glowing Bear app. That's neat! Apparently, it should also be possible to connect from an android app. More clients here.