Re: [PATCH] sched/topology: Use Identity node only if required

From: Peter Zijlstra
Date: Fri Aug 31 2018 - 06:41:39 EST


On Fri, Aug 31, 2018 at 03:22:48AM -0700, Srikar Dronamraju wrote:

> At boot: Before topology update.

How does that work; you do SMP bringup _before_ you know the topology !?

> After topology update.
>
> For CPU 0
> domain-0: span=0-7 level=SMT
> groups: 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 6:{ span=6 }, 7:{ span=7 }
> domain-1: span=0-7,32-39,64-71,96-103,128-135,160-167,192-199,224-231,256-263,288-295 level=DIE
> groups: 0:{ span=0-7 cap=8192 }, 32:{ span=32-39 cap=8192 }, 64:{ span=64-71 cap=8192 }, 96:{ span=96-103 cap=8192 }, 128:{ span=128-135 cap=8192 }, 160:{ span=160-167 cap=8192 }, 192:{ span=192-199 cap=8192 }, 224:{ span=224-231 cap=8192 }, 256:{ span=256-263 cap=8192 }, 288:{ span=288-295 cap=8192 }
> domain-2: span=0-303 level=NODE
> groups: 0:{ span=0-7,32-39,64-71,96-103,128-135,160-167,192-199,224-231,256-263,288-295 cap=81920 }, 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }, 16:{ span=16-23,48-55,80-87,112-119,144-151,176-183,208-215,240-247,272-279 cap=73728 }, 24:{ span=24-31,56-63,88-95,120-127,152-159,184-191,216-223,248-255,280-287 cap=73728 }
>
> For CPU 1
> domain-0: span=0-7 level=SMT
> groups: 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 6:{ span=6 }, 7:{ span=7 }, 0:{ span=0 }
> domain-1: span=0-7,32-39,64-71,96-103,128-135,160-167,192-199,224-231,256-263,288-295 level=DIE
> groups: 0:{ span=0-7 cap=8192 }, 32:{ span=32-39 cap=8192 }, 64:{ span=64-71 cap=8192 }, 96:{ span=96-103 cap=8192 }, 128:{ span=128-135 cap=8192 }, 160:{ span=160-167 cap=8192 }, 192:{ span=192-199 cap=8192 }, 224:{ span=224-231 cap=8192 }, 256:{ span=256-263 cap=8192 }, 288:{ span=288-295 cap=8192 }
> domain-2: span=0-303 level=NODE
> groups: 0:{ span=0-7,32-39,64-71,96-103,128-135,160-167,192-199,224-231,256-263,288-295 cap=81920 }, 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }, 16:{ span=16-23,48-55,80-87,112-119,144-151,176-183,208-215,240-247,272-279 cap=73728 }, 24:{ span=24-31,56-63,88-95,120-127,152-159,184-191,216-223,248-255,280-287 cap=73728 }
>
>
> For CPU 8
> domain-0: span=8-15 level=SMT
> groups: 8:{ span=8 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 12:{ span=12 }, 13:{ span=13 }, 14:{ span=14 }, 15:{ span=15 }
> domain-1: span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 level=DIE
> groups: 8:{ span=8-15 cap=8192 }, 40:{ span=40-47 cap=8192 }, 72:{ span=72-79 cap=8192 }, 104:{ span=104-111 cap=8192 }, 136:{ span=136-143 cap=8192 }, 168:{ span=168-175 cap=8192 }, 200:{ span=200-207 cap=8192 }, 232:{ span=232-239 cap=8192 }, 264:{ span=264-271 cap=8192 }, 296:{ span=296-303 cap=8192 }
> domain-2: span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 level=NODE
> groups: 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }
> domain-3: span=0-303 level=NUMA
> groups: 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }, 16:{ span=16-23,48-55,80-87,112-119,144-151,176-183,208-215,240-247,272-279 cap=73728 }, 24:{ span=24-31,56-63,88-95,120-127,152-159,184-191,216-223,248-255,280-287 cap=73728 }
> ERROR: groups don't span domain->span
>
> For CPU 9
> domain-0: span=8-15 level=SMT
> groups: 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 12:{ span=12 }, 13:{ span=13 }, 14:{ span=14 }, 15:{ span=15 }, 8:{ span=8 }
> domain-1: span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 level=DIE
> groups: 8:{ span=8-15 cap=8192 }, 40:{ span=40-47 cap=8192 }, 72:{ span=72-79 cap=8192 }, 104:{ span=104-111 cap=8192 }, 136:{ span=136-143 cap=8192 }, 168:{ span=168-175 cap=8192 }, 200:{ span=200-207 cap=8192 }, 232:{ span=232-239 cap=8192 }, 264:{ span=264-271 cap=8192 }, 296:{ span=296-303 cap=8192 }
> domain-2: span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 level=NODE
> groups: 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }
> domain-3: span=0-303 level=NUMA
> groups: 8:{ span=8-15,40-47,72-79,104-111,136-143,168-175,200-207,232-239,264-271,296-303 cap=81920 }, 16:{ span=16-23,48-55,80-87,112-119,144-151,176-183,208-215,240-247,272-279 cap=73728 }, 24:{ span=24-31,56-63,88-95,120-127,152-159,184-191,216-223,248-255,280-287 cap=73728 }
> ERROR: groups don't span domain->span

This is all very confused... and does not include the error we saw
earlier.

CPU 0 has: SMT, DIE, NODE
CPU 8 has: SMT, DIE, NODE, NUMA

Something is completely buggered in your topology setup.