From: Michael Ellerman <mpe@ellerman.id.au>
To: Sandipan Das <sandipan@linux.ibm.com>
Cc: srikar@linux.vnet.ibm.com, kamalesh@linux.vnet.ibm.com,
shiganta@in.ibm.com, nasastry@in.ibm.com, harish@linux.ibm.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] selftests: powerpc: Fix online CPU selection
Date: Wed, 29 Jul 2020 23:47:31 +1000 [thread overview]
Message-ID: <87r1su5t70.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200609073733.997643-1-sandipan@linux.ibm.com>
Sandipan Das <sandipan@linux.ibm.com> writes:
> The size of the CPU affinity mask must be large enough for
> systems with a very large number of CPUs. Otherwise, tests
> which try to determine the first online CPU by calling
> sched_getaffinity() will fail. This makes sure that the size
> of the allocated affinity mask is dependent on the number of
> CPUs as reported by get_nprocs().
>
> Fixes: 3752e453f6ba ("selftests/powerpc: Add tests of PMU EBBs")
> Reported-by: Shirisha Ganta <shiganta@in.ibm.com>
> Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
> ---
> Previous versions can be found at:
> v1: https://lore.kernel.org/linuxppc-dev/20200608144212.985144-1-sandipan@linux.ibm.com/
>
> Changes in v2:
> - Added NULL check for the affinity mask as suggested by Kamalesh.
> - Changed "cpu set" to "CPU affinity mask" in the commit message.
This sometimes breaks, eg:
# ./count_instructions
test: count_instructions
tags: git_version:v5.8-rc2-327-g9a1d992a7eb7
sched_getaffinity: Invalid argument
[FAIL] Test FAILED on line 123
failure: count_instructions
This system has a messed up SMT setup, but the old code was able to cope
with it:
# ppc64_cpu --info
Core 0: 0* 1* 2 3 4 5 6 7
Core 1: 8 9 10* 11* 12 13 14 15
Core 2: 16 17 18 19 20 21 22 23
Core 3: 24 25 26 27 28 29 30 31
Core 4: 32 33 34 35 36 37 38 39
Core 5: 40 41 42 43 44 45 46 47
Core 6: 48 49 50 51 52 53 54 55
Core 7: 56 57 58 59 60 61 62 63
Core 8: 64 65 66 67 68 69 70 71
Core 9: 72 73 74 75 76 77 78 79
Core 10: 80 81 82 83 84 85 86 87
Core 11: 88 89 90 91 92 93 94 95
Core 12: 96 97 98 99 100* 101* 102* 103*
Core 13: 104* 105* 106* 107* 108* 109* 110* 111*
Core 14: 112* 113* 114* 115* 116* 117* 118* 119*
Core 15: 120 121 122 123 124 125 126 127
Core 16: 128 129 130 131 132 133 134 135
Core 17: 136 137 138 139 140 141 142 143
Core 18: 144 145 146 147 148 149 150 151
Core 19: 152 153 154 155 156 157 158 159
cheers
next prev parent reply other threads:[~2020-07-29 13:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-09 7:37 [PATCH v2] selftests: powerpc: Fix online CPU selection Sandipan Das
2020-07-29 13:47 ` Michael Ellerman [this message]
2020-07-29 16:03 ` Srikar Dronamraju
2020-07-30 4:59 ` Sandipan Das
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