linux_dsm_epyc7002/arch
Anju T Sudhakar 684d984038 powerpc/powernv: Add debugfs interface for imc-mode and imc-command
In memory Collection (IMC) counter pmu driver controls the ucode's
execution state. At the system boot, IMC perf driver pause the ucode.
Ucode state is changed to "running" only when any of the nest units
are monitored or profiled using perf tool.

Nest units support only limited set of hardware counters and ucode is
always programmed in the "production mode" ("accumulation") mode. This
mode is configured to provide key performance metric data for most of
the nest units.

But ucode also supports other modes which would be used for "debug" to
drill down specific nest units. That is, ucode when switched to
"powerbus" debug mode (for example), will dynamically reconfigure the
nest counters to target only "powerbus" related events in the hardware
counters. This allows the IMC nest unit to focus on powerbus related
transactions in the system in more detail. At this point, production
mode events may or may not be counted.

IMC nest counters has both in-band (ucode access) and out of band
access to it. Since not all nest counter configurations are supported
by ucode, out of band tools are used to characterize other nest
counter configurations.

Patch provides an interface via "debugfs" to enable the switching of
ucode modes in the system. To switch ucode mode, one has to first
pause the microcode (imc_cmd), and then write the target mode value to
the "imc_mode" file.

Proposed Approach:

In the proposed approach, the function (export_imc_mode_and_cmd) which
creates the debugfs interface for imc mode and command is implemented
in opal-imc.c. Thus we can use imc_get_mem_addr() to get the homer
base address for each chip.

The interface to expose imc mode and command is required only if we
have nest pmu units registered. Employing the existing data structures
to track whether we have any nest units registered will require to
extend data from perf side to opal-imc.c. Instead an integer is
introduced to hold that information by counting successful nest unit
registration. Debugfs interface is removed based on the integer count.

Example for the interface:

  $ ls /sys/kernel/debug/imc
  imc_cmd_0  imc_cmd_8  imc_mode_0  imc_mode_8

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-19 23:05:00 +11:00
..
alpha treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
arc ARC updates for 4.15-rc1 2017-11-25 08:21:54 -10:00
arm Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-12-03 10:51:08 -05:00
arm64 arm64 fixes: 2017-12-01 19:37:03 -05:00
blackfin treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
c6x Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
cris pci-v4.15-changes 2017-11-15 15:01:28 -08:00
frv Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
h8300 mm, arch: remove empty_bad_page* 2017-11-15 18:21:03 -08:00
hexagon Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
ia64 arch/ia64/include/asm/topology.h: remove unused parent_node() macro 2017-11-17 16:10:04 -08:00
m32r m32r: fix endianness constraints 2017-11-15 18:21:00 -08:00
m68k m68k/macboing: Fix missed timer callback assignment 2017-11-24 16:19:40 +01:00
metag DeviceTree for 4.15: 2017-11-14 18:25:40 -08:00
microblaze Microblaze patch for 4.15-rc2 2017-11-29 14:19:22 -08:00
mips * x86 bugfixes: APIC, nested virtualization, IOAPIC 2017-11-30 08:15:19 -08:00
mn10300 bug: define the "cut here" string in a single place 2017-11-17 16:10:01 -08:00
nios2 DeviceTree for 4.15: 2017-11-14 18:25:40 -08:00
openrisc kmemcheck: remove annotations 2017-11-15 18:21:04 -08:00
parisc treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
powerpc powerpc/powernv: Add debugfs interface for imc-mode and imc-command 2018-01-19 23:05:00 +11:00
riscv RISC-V: Fixes for clean allmodconfig build 2017-12-01 13:31:31 -08:00
s390 * x86 bugfixes: APIC, nested virtualization, IOAPIC 2017-11-30 08:15:19 -08:00
score License cleanup: add SPDX license identifier to uapi header files with no license 2017-11-02 11:19:54 +01:00
sh treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
sparc Merge branch 'akpm' (patches from Andrew) 2017-11-29 19:12:44 -08:00
tile mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE 2017-11-29 18:40:42 -08:00
um This pull request contains the following core changes: 2017-11-22 20:46:06 -10:00
unicore32 kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2017-11-15 18:21:04 -08:00
x86 * x86 bugfixes: APIC, nested virtualization, IOAPIC 2017-11-30 08:15:19 -08:00
xtensa libnvdimm for 4.15 2017-11-17 09:51:57 -08:00
.gitignore
Kconfig bpf: Revert bpf_overrid_function() helper changes. 2017-11-11 18:24:55 +09:00