456bb0b97f
A debugfs interface /sys/kernel/debug/iommu/intel/dmar_perf_latency is created to control and show counts of execution time ranges for various types per DMAR. The interface may help debug any potential performance issue. By default, the interface is disabled. Possible write value of /sys/kernel/debug/iommu/intel/dmar_perf_latency 0 - disable sampling all latency data 1 - enable sampling IOTLB invalidation latency data 2 - enable sampling devTLB invalidation latency data 3 - enable sampling intr entry cache invalidation latency data 4 - enable sampling prq handling latency data Read /sys/kernel/debug/iommu/intel/dmar_perf_latency gives a snapshot of sampling result of all enabled monitors. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20210520031531.712333-1-baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20210610020115.1637656-15-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>