Linux perf tool support

Hello, I was wondering if any of you would know about the progress regarding the support for the perf tool in RiscV.

After installing the latest Linux kernel and the perf command line tool (that was on a HiFive Unleashed) I realized there wasn’t support for perf events. After investigating a bit, I found multiple pages mentioning the lack of performance counter overflow interrupts in the RiscV specification to be the main problem.

Is that indeed the problem? Do you know if there is some work to add that feature to the RiscV specification? Or maybe a workaround?

Thanks.

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There’s some recent discussion about improving hardware performance counters on the RISC-V mailing lists: https://lists.riscv.org/g/tech-privileged/topic/a_proposal_to_enhance_risc_v/75675990?p=Created,,,20,1,0,0::recentpostdate%2Fsticky,,,20,2,0,75675990#

Worked on kernel 5.5.6 and enabled following kernel configurations

CONFIG_CGROUP_PERF
CONFIG_HAVE_PERF_EVENTS
CONFIG_PERF_USE_VMALLOC
CONFIG_PERF_EVENTS
CONFIG_DEBUG_PERF_USE_VMALLOC
CONFIG_TRACEPOINTS

Verified the perf events on Hi-Five unleashed Board.