[PATCH v2 0/3] Enable the profiling of EL0&1 translation regime of ARM SPE
Yicong Yang
yangyicong at huawei.com
Wed Nov 29 23:46:06 PST 2023
From: Yicong Yang <yangyicong at hisilicon.com>
When using the SPE, it's noticed the operation of a VM is not profiled at
all on a VHE enabled host. This is because the driver's using
PMSCR_EL1.{E1SPE, E0SPE} to enable the profiling. On a VHE enabled host,
we're actually setting the PMSCR_EL2.{E2SPE, E0SPE}. This will enable the
profiling of EL2 and EL0 in a EL2&0 translation regime. However the VM
is using a EL1&0 translation regime, so it's not profiled. We can enable
the profiling of EL1&0 translation regime by setting PMSCR_EL12.{E1SPE, E0SPE}
from EL2.
This patch adds the support to this by:
- Add the sysreg definition of PMSCR_EL12
- Factor the code to allow extension
- Enable the profiling of EL1&0 and complete perf's exclude_* option
Tests have been done on VHE and non-VHE host with
`perf record -e {arm_spe_0//}:u|k|h|G|h`
and results shows as expected.
The sample from El0 in the VM will be like (generated by `perf report -D`):
. 000003b8: b0 48 eb 12 ab ff ff 00 80 PC 0xffffab12eb48 el0 ns=1
. 000003c1: 99 07 00 LAT 7 ISSUE
. 000003c4: 98 08 00 LAT 8 TOT
. 000003c7: 62 42 00 00 00 EV RETIRED NOT-TAKEN
. 000003cc: 4a 01 B COND
. 000003ce: 00 00 PAD
. 000003d0: b1 4c eb 12 ab ff ff 00 80 TGT 0xffffab12eb4c el0 ns=1
. 000003d9: 00 00 00 PAD
. 000003dc: 64 50 01 00 00 CONTEXT 0x150 el1
. 000003e1: 65 3c 11 00 00 CONTEXT 0x113c el2
. 000003e6: 00 00 00 00 00 PAD
. 000003eb: 71 aa aa 00 fd 06 00 00 00 TS 30014483114
Change since v1:
- Add tag by Mark and ordered PMSCR_EL12 by address as suggested. By now at least
PMSCR_EL12 keeps order among its *_EL12 siblings in sysreg.
Link: https://lore.kernel.org/linux-arm-kernel/20231122084602.53914-1-yangyicong@huawei.com/
Yicong Yang (3):
arm64/sysreg: Add PMSCR_EL12 and factor out the common fields
perf: arm_spe: Factor out PMSCR set/clear operations
perf: arm_spe: Enable the profiling of EL0&1 translation regime
arch/arm64/tools/sysreg | 10 ++++-
drivers/perf/arm_spe_pmu.c | 76 ++++++++++++++++++++++++++++----------
2 files changed, 65 insertions(+), 21 deletions(-)
--
2.24.0
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