ACK: [SRU][J:linux-bluefield][PATCH v1 0/2] Enhancements to mlxbf-pmc

[Bartlomiej Zolnierkiewicz]

Acked-by: Bartlomiej Zolnierkiewicz <bartlomiej.zolnierkiewicz at canonical.com>

On Thu, Nov 2, 2023 at 7:22 AM Shravan Kumar Ramani
<shravankr at nvidia.com> wrote:
>
> This submission contains 2 patches:
>
> 1. Support for 64-bit counters and monitoring cycle counts
>
> BugLink: https://bugs.launchpad.net/bugs/2042525
>
> SRU Justification:
>
> [Impact]
> Currently, there is no method to keep track of the cycle count when an event
> is being monitored. And since cycle count increments quickly, the 32-bit counter
> values could wrap around and hence support for 64-bit counters is also needed
> for the same.
>
> [Fix]
> Expose 2 additional sysfs entries: count_clock and use_odd_counter. These fields
> are supported in BlueField-3 PMC hardware and each bit in count_clock
> corresponds to each counter, while each bit in use_odd_counter corresponds to an
> even counter.
> Exposing these fields will allow the user to program any counter of choice to
> monitor the cycle count for the required duration.
> Similarly, use_odd_counter can be set to couple 2 adjacent odd and even counters
> to form a 64-bit counter.
>
> [Test Case]
> 1. Verify that count_clock and use_odd_counter sysfs entries are created for
> each BlueField-3 HW block.
> These are not supported by BlueField-1 or BlueField-2 HW.
> 2. Set any bit in count_clock and check if the corresponding counter values
> increment after enabling.
> 3. Set any bit in use_odd_counter and check if the cycle count increments on
> 2 counters with the odd counter being the lower 32 bits and the even counter
> being the upper 32 bits.
>
> [Regression Potential]
> Can be considered minimal.
>
> 2. Addition of clock_measure performance events
>
> BugLink: https://bugs.launchpad.net/bugs/2042527
>
> SRU Justification:
>
> [Impact]
> Currently, the counters under the clock_measure HW block are not supported by
> the driver and is a new requirement for calculating performance metrics.
>
> [Fix]
> Add support for "clock_measure" block by passing the block info via ACPI.
> The events monitored by these counters is added to the driver and exposed via
> a new sysfs sub-directory for this block.
>
> [Test Case]
> Read any of the registers listed under the "clock_measure" sub-directory.
> These fields are read-only and hence all writes will be blocked by the driver.
>
> [Regression Potential]
> Can be considered minimal.
>
> Shravan Kumar Ramani (2):
>   UBUNTU: SAUCE: mlxbf-pmc: Add support for 64-bit counters and cycle
>     count
>   UBUNTU: SAUCE: mlxbf-pmc: Add support for clock_measure performance
>     block
>
>  drivers/platform/mellanox/mlxbf-pmc.c | 174 +++++++++++++++++++++++++-
>  1 file changed, 170 insertions(+), 4 deletions(-)
>