intel_spr_sde_test fails now and then.

[charris]

The basic cause seems to be due to changing fp mode

    @pytest.fixture(scope="function", autouse=True)
    def check_fpu_mode(request):
        """
        Check FPU precision mode was not changed during the test.
        """
        old_mode = get_fpu_mode()
        yield
        new_mode = get_fpu_mode()
    
        if old_mode != new_mode:
>           raise AssertionError("FPU precision mode changed from {0:#x} to {1:#x}"
                                 " during the test".format(old_mode, new_mode))
E           AssertionError: FPU precision mode changed from 0x37f to 0x77f during the test

new_mode   = 1919
old_mode   = 895

There are also some wrong results, but I suspect they are related to the fp mode.
See https://github.com/numpy/numpy/actions/runs/4631776714/jobs/8195205969?pr=23542 for more detail.

@r-devulap Thoughts?

[r-devulap]

Interesting, it doesn't always fail. Not sure why this happens but I am taking a look.

[charris]

I messed up the title here, the failing test is intel_spr_sde_test.

[r-devulap]

disabling the ci job until I figure out what's happening #23566

[r-devulap]

closing. #24268 fixes it.

[ngoldbaum]

This is happening again, https://github.com/numpy/numpy/actions/runs/5716892291/job/15489817515?pr=24188

[r-devulap]

This is happening again, https://github.com/numpy/numpy/actions/runs/5716892291/job/15489817515?pr=24188

Taking a look.

[r-devulap]

Looks like it was only partially fixed :( I found more AVX-512 use cases where the bug still persists. Will disable the test, again! Minimal reproducer:

import numpy as np
from numpy.core._multiarray_tests import get_fpu_mode

print("fpu mode before exp2", hex(get_fpu_mode()))
np.exp2(1)
print("fpu mode after exp2", hex(get_fpu_mode()))
print("fpu mode before log2", hex(get_fpu_mode()))
np.log2(1)
print("fpu mode after log2", hex(get_fpu_mode()))

Command to run in SDE: sde-external-9.24.0-2023-07-13-lin/sde64 -skx -- python3 temp.py

Output:

fpu mode before exp2 0x37f
fpu mode after exp2 0x77f
fpu mode before log2 0x77f
fpu mode after log2 0x37f

[seiko2plus]

@r-devulap, The changes happens to reserved bits of x87 FPU control word, so get_fpu_mode() need to be masked to avoid testing these bits. So I'm going to enable SDE spr tests again after patching before/after get_fpu_mode() comparison on x86

[seiko2plus]

My apologies; it wasn't the reserved bits, but rather the rounding control bits. Some AVX512(BW/DW) instructions exhibited a bug due to counting the FPU control to emulate on-the-fly(IMM rounding bits) rounding without restoring the previous state.

[r-devulap]

I completely missed the SDE version 9.27 which has been available for a couple of months now. Updated CI to use this version and run tests on SPR. See c4e790b from #25376

[r-devulap]

SDE tests are enabled on TGL and SPR platforms. I can finally close this :)