On 09/09/25 2:32 am, Mukesh Kumar Chaurasiya wrote:
Adding support for the generic irq entry/exit handling for PowerPC. The
goal is to bring PowerPC in line with other architectures that already
use the common irq entry infrastructure, reducing duplicated code and
making it easier to share future changes in entry/exit paths.
This is slightly tested on ppc64le.
The performance benchmarks from perf bench basic syscall are below:
| Metric | W/O Generic Framework | With Generic Framework | Improvement |
| ---------- | --------------------- | ---------------------- | ----------- |
| Total time | 0.885 [sec] | 0.880 [sec] | ~0.56% |
| usecs/op | 0.088518 | 0.088005 | ~0.58% |
| ops/sec | 1,12,97,086 | 1,13,62,977 | ~0.58% |
Thats close to 0.6% improvement with this.
Changelog:
V1 -> V2: Support added for irq with generic framework.
Mukesh Kumar Chaurasiya (8):
powerpc: rename arch_irq_disabled_regs
powerpc: Prepare to build with generic entry/exit framework
powerpc: introduce arch_enter_from_user_mode
powerpc: Introduce syscall exit arch functions
powerpc: add exit_flags field in pt_regs
powerpc: Prepare for IRQ entry exit
powerpc: Enable IRQ generic entry/exit path.
powerpc: Enable Generic Entry/Exit for syscalls.
arch/powerpc/Kconfig | 2 +
arch/powerpc/include/asm/entry-common.h | 550 ++++++++++++++++++++++++
arch/powerpc/include/asm/hw_irq.h | 4 +-
arch/powerpc/include/asm/interrupt.h | 393 +++--------------
arch/powerpc/include/asm/ptrace.h | 2 +
arch/powerpc/include/asm/stacktrace.h | 8 +
arch/powerpc/include/asm/syscall.h | 5 +
arch/powerpc/include/asm/thread_info.h | 1 +
arch/powerpc/include/uapi/asm/ptrace.h | 14 +-
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/interrupt.c | 251 ++---------
arch/powerpc/kernel/interrupt_64.S | 2 -
arch/powerpc/kernel/ptrace/ptrace.c | 142 +-----
arch/powerpc/kernel/signal.c | 8 +
arch/powerpc/kernel/syscall.c | 119 +----
arch/powerpc/kernel/traps.c | 2 +-
arch/powerpc/kernel/watchdog.c | 2 +-
arch/powerpc/perf/core-book3s.c | 2 +-
18 files changed, 698 insertions(+), 810 deletions(-)
create mode 100644 arch/powerpc/include/asm/entry-common.h
Hi,
I have reviewed and tested the generic IRQ entry/exist patch series.
Below are my observations:
Test Coverage
• Successfully ran LTP (specially syscall) and entire LTP test
suite, without observing any regressions or issues related to the
implementation.
System Configuration
• CPUs: 640
• Kernel: v6.17.0-rc6+
• Processor mode: Shared (uncapped)
Performance Evaluation
• Conducted benchmarking using perf bench syscall basic -l.
• No functional regressions observed, and results were
consistent with expectations.
The performance benchmarks from perf bench basic syscall are below:
Loops = 100,000 | Metric | W/O Generic Framework | With Generic
Framework | Improvement |
|----------|-----------------------:|-----------------------:|------------:|
| usecs/op | 0.124562 | 0.124253 | ~0.25% | | ops/sec | 8,028,471 |
8,048,158 | ~0.25% | Loops = 1,000,000 | Metric | W/O Generic Framework
| With Generic Framework | Improvement |
|----------|-----------------------:|-----------------------:|------------:|
| usecs/op | 0.125389 | 0.124374 | ~0.81% | | ops/sec | 7,977,511 |
8,040,330 | ~0.79% | Loops = 10,000,000 | Metric | W/O Generic Framework
| With Generic Framework | Improvement |
|----------|-----------------------:|-----------------------:|------------:|
| usecs/op | 0.124626 | 0.123928 | ~0.56% | | ops/sec | 8,024,058 |
8,069,182 | ~0.56% | **Overall (aggregated across all runs)** | Metric |
W/O Generic Framework | With Generic Framework | Improvement | |
---------- |
---------------------:|-----------------------:|------------:| | Total
time | 1.384 [sec] | 1.376 [sec] | ~0.58% | | usecs/op | 0.124694 |
0.123971 | ~0.58% | | ops/sec | 8,019,904 | 8,066,393 | ~0.58% |
Here with this benchmarking we can see the improvement close to 0.6%.
Overall, the patch series works as intended in my testing.
Please add below tag for the patch set.
Tested-by: Samir M <[email protected]>
Thank You !!
