[PATCH v3 0/5] Add support for T-HEAD C9xx PMU extensions

[Heiko Stübner]

Am Donnerstag, 8. September 2022, 18:07:59 CEST schrieb Anup Patel:
> Hi Heiko,
> 
> On Thu, Sep 8, 2022 at 7:13 PM Heiko Stuebner <heiko at sntech.de> wrote:
> >
> > The T-HEAD C9XX cores implement functionality very similar to SSCOFPMF.
> > Instead of implementing a separate interface into SBI as done in v1,
> > we can add the C9XX tidbits with quite minimal overhead and leaverage
> > the existing SBI pmu interface including giving access to the firmware
> > counters.
> >
> > The current only hickup is the detection override in sbi_hart, where
> > I still need to find out why the MHPMCOUNTERs are not writeable
> > at _that_ point of the boot, but with this series on top of openSBI 1.1
> > and the matching kernel perf patch I get reasonable results for example
> > for:
> >
> > perf stat -e cycles -e instructions -e L1-icache-load-misses -e L1-icache-loads ls
> >
> >  Performance counter stats for 'ls':
> >
> >           17119496      cycles
> >            2867765      instructions              #    0.17  insn per cycle
> >              55929      L1-icache-load-misses     #    1.61% of all L1-icache accesses
> >            3467346      L1-icache-loads
> >
> >        0.030156216 seconds time elapsed
> >
> >        0.000000000 seconds user
> >        0.023496000 seconds sys
> >
> > changes in v3:
> > - follow Atish's advice and implement an abstraction
> >   to not pollute the core pmu with cpu-specific variants
> >
> > changes in v2:
> > - don't implement a separate interface but instead modify
> >   the sbi-pmu to allow the c9xx to use standard pmu interface
> >
> >
> > Heiko Stuebner (5):
> >   lib: sbi: do platform-specific extension population earlier
> >   lib: sbi_pmu: move pmu irq information into pmu itself
> >   lib: sbi_pmu: add ability to override methods on non-standard
> >     platforms
> >   platform: generic: add extensions_init handler and platform-override
> >   platform: generic: allwinner: add support for c9xx pmu
> 
> Please rebase this upon the latest OpenSBI. We already have
> "struct sbi_pmu_device" which platform can register and you
> can extend it in this series.

oh interesting, that sneaked past me it seems :-)
Will update to use this.

Thanks
Heiko

> >
> >  include/sbi/sbi_pmu.h                        |  16 +++
> >  lib/sbi/sbi_hart.c                           |  21 ++-
> >  lib/sbi/sbi_pmu.c                            |  31 +++++
> >  platform/generic/allwinner/sun20i-d1.c       |  76 +++++++++++
> >  platform/generic/include/platform_override.h |   1 +
> >  platform/generic/include/thead_c9xx.h        | 127 +++++++++++++++++++
> >  platform/generic/platform.c                  |   9 ++
> >  7 files changed, 274 insertions(+), 7 deletions(-)
> >  create mode 100644 platform/generic/include/thead_c9xx.h
> >
> > --
> > 2.35.1
> >
> >
> > --
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>