perf/x86/intel/uncore: Support IIO free-running counters on SKX
As of Skylake Server, there are a number of free running counters in each IIO Box that collect counts of per-box IO clocks and per-port Input/Output x BW/Utilization. The free running counters cannot be part of the existing IIO BOX, because, quoting from Peter Zijlstra: "This will result in some (probably) unexpected scheduling artifacts. Probably the only way to really cure that is to have the free running counters in their own PMU and not share with the GP counters of this box." So let's add a new PMU for the free running counters, as suggested. The free-running counter is read-only and always active. Counting will be suspended only when the IIO Box is powered down. There are three types of IIO free-running counters on Skylake server, IO CLOCKS counter, BANDWIDTH counters and UTILIZATION counters. IO CLOCKS counter is a clock of IIO box. BANDWIDTH counters are to count inbound(PCIe->CPU)/outbound(CPU->PCIe) bandwidth. UTILIZATION counters are to count input/output utilization. The bit width of the free-running counters is 36-bits. Suggested-by:Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
Kan Liang <kan.liang@intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@kernel.org Cc: eranian@google.com Link: http://lkml.kernel.org/r/1525371913-10597-6-git-send-email-kan.liang@intel.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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