pmcstat on selected cpu -- posible bug?

[Slawa Olhovchenkov]

On Sat, Jun 27, 2015 at 03:08:35PM +0300, Slawa Olhovchenkov wrote:

> I have dual-socket E5v3 system and try to profiling source of CPU load
> on first socket.

I am try some expirement and this is like incorrect CPU(socket)/core
selecting: selecting '-c 0' allocate system mode PMCs on 'core 0' for
all sockets, not for only 'core 0 socket 0'.

> cpuset -l 1 pmcstat -S CPU_CLK_UNHALTED_CORE -l 10 -c 1 -n 500 -O sample.out
> pmcstat -R sample.out -G out.txt -k /boot/kernel.VSTREAM
> cat out.txt | ./stackcollapse-pmc.pl | ./flamegraph.pl --width=1200 > cpi.svg
> 
> cpi.svg can be see at http://zxy.spb.ru/cpi.svg
> 
> I see many times send in t4_intr, but all chelsio interrupt handlers (t4_intr)
> binded to second CPU socket:
> 
> # vmstat -i
> interrupt                          total       rate
> irq9: acpi0                            4          0
> irq18: ehci0 ehci1               2893412          2
> irq19: xhci0                     3185327          2
> cpu0:timer                    1532629922       1093
> irq264: mps0                  1399546223        998
> irq265: mps1                  3638584876       2595
> irq266: ahci0                 3049531638       2175
> irq267: ahci1                  707587584        504
> irq268: mps2                  6161214642       4395
> irq270: t5nex0:evt                     4          0
> irq281: t5nex0:1.0           62811267214      44810
> irq282: t5nex0:1.1           63080900542      45002
> irq283: t5nex0:1.2           62979721970      44930
> irq284: t5nex0:1.3           62968826175      44922
> irq285: t5nex0:1.4           62963754266      44918
> irq286: t5nex0:1.5           63303732253      45161
> irq287: t5nex0:1.6           63012633949      44953
> irq288: t5nex0:1.7           63538714658      45328
> irq289: t5nex0:1,0                 73899          0
> irq290: t5nex0:1,1                111666          0
> cpu3:timer                    1534027652       1094
> cpu6:timer                    1546786165       1103
> cpu13:timer                   1588099533       1132
> cpu2:timer                    1534703017       1094
> cpu7:timer                    1553306409       1108
> cpu9:timer                    1586733982       1131
> cpu1:timer                    1538685850       1097
> cpu8:timer                    1587569958       1132
> cpu5:timer                    1537756504       1097
> cpu12:timer                   1585898180       1131
> cpu4:timer                    1530812247       1092
> cpu10:timer                   1586851448       1132
> cpu15:timer                   1586024994       1131
> cpu11:timer                   1587022608       1132
> cpu14:timer                   1586503852       1131
> Total                       544625692623     388539
> 
> # cpuset -g -x 281
> irq 281 mask: 8
> irq 282 mask: 9
> irq 283 mask: 10
> irq 284 mask: 11
> irq 285 mask: 12
> irq 286 mask: 13
> irq 287 mask: 14
> irq 288 mask: 15
> irq 289 mask: 8
> irq 290 mask: 12
> 
> Cross-checked by dtrace:
> # dtrace -n '::t4_intr:entry { @[stringof(curthread->td_name), curthread->td_oncpu] = count(); }'
> dtrace: description '::t4_intr:entry ' matched 1 probe
> ^C
> 
>   irq282: t5nex0:1.1                                   9           361413
>   irq281: t5nex0:1.0                                   8           361573
>   irq285: t5nex0:1.4                                  12           364535
>   irq283: t5nex0:1.2                                  10           365919
>   irq284: t5nex0:1.3                                  11           366386
>   irq287: t5nex0:1.6                                  14           367603
>   irq286: t5nex0:1.5                                  13           368409
>   irq288: t5nex0:1.7                                  15           371441
> 
> What is wrong? Bug in pmcstat?
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