en Copyright 2015 Java http://172.16.0.5:8080/history/linux-6.15/Documentation/ABI/testing/sysfs-bus-event_source-devices-caps#571d91dc perf: Add branch stack countersCurrently, the additional information of a branch entry is stored in au64 space. With more and more information added, the space is runningout. For example, the information of occurrences of events will be addedfor each branch.Two places were suggested to append the counters.https://lore.kernel.org/lkml/20230802215814.GH231007@hirez.programming.kicks-ass.net/One place is right after the flags of each branch entry. It changes theexisting struct perf_branch_entry. The later ARCH specificimplementation has to be really careful to consistently pickthe right struct.The other place is right after the entire struct perf_branch_stack.The disadvantage is that the pointer of the extra space has to berecorded. The common interface perf_sample_save_brstack() has to beupdated.The latter is much straightforward, and should be easily understood andmaintained. It is implemented in the patch.Add a new branch sample type, PERF_SAMPLE_BRANCH_COUNTERS, to indicatethe event which is recorded in the branch info.The "u64 counters" may store the occurrences of several events. Theinformation regarding the number of events/counters and the width ofeach counter should be exposed via sysfs as a reference for the perftool. Define the branch_counter_nr and branch_counter_width ABI here.The support will be implemented later in the Intel-specific patch.Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>Signed-off-by: Kan Liang <kan.liang@linux.intel.com>Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>Link: https://lkml.kernel.org/r/20231025201626.3000228-1-kan.liang@linux.intel.com List of files: /linux-6.15/Documentation/ABI/testing/sysfs-bus-event_source-devices-caps Wed, 25 Oct 2023 20:16:19 +0000 Kan Liang <kan.liang@linux.intel.com> http://172.16.0.5:8080/history/linux-6.15/Documentation/ABI/testing/sysfs-bus-event_source-devices-caps#999d7c47 docs: ABI: sysfs-bus-event_source-devices: Document sysfs caps entry for PMUDetails is added about "caps" attribute group in the ABI documentation.This is used to expose some of the PMU attributes in "caps"directory under : /sys/bus/event_source/devices/<dev>/. The dev/capswill contain information about features that platform specific PMUsupports.Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>Link: https://lore.kernel.org/r/20220520084630.15181-2-atrajeev@linux.vnet.ibm.com List of files: /linux-6.15/Documentation/ABI/testing/sysfs-bus-event_source-devices-caps Fri, 20 May 2022 08:46:30 +0000 Athira Rajeev <atrajeev@linux.vnet.ibm.com>