Commonly Used Metrics for Performance Analysis - Power.org

Metrics for Performance Analysis15 L2 Read-Claim Machine MetricsThis chapter lists and describes the events, metrics and groups needed to characterize how the L2 readclaimmachines for each chip are utilized across the system. Each POWER7 system can configure nodepump or system pump mode, so these metrics provide information for tuning the system appropriately.15.1Descriptions of EventsThere are 2 events, distributed across 2 event groups, needed for these POWER7 L2 cache statistics.This section provides more details on each event and how it is triggered.PM_L2_NODE_PUMPRC req that was a local (aka node) pump attemptThe L2 Read Claim machine performed a local (chip) pump attempt. This event is delivered from the L2domain, so must be scaled accordingly (divide by 2)PM_L2_SYS_PUMPRC req that was a global (aka system) pump attemptThe L2 Read Claim machine performed a global (system) pump attempt. This event is delivered from the L2domain, so must be scaled accordingly (divide by 2)15.2MetricsL2 read-claim machine behavior is characterized with the following metrics:L2_Node_Pumps(%)L2 Node pumps as a % of all L2 pumpsFormula: ( PM_L2_NODE_PUMP ) / (PM_L2_NODE_PUMP + PM_L2_SYS_PUMP) * 100L2_Sys_Pumps(%)L2 Sys pumps per core as a % of all L2 pumpsFormula: ( PM_L2_SYS_PUMP ) / (PM_L2_NODE_PUMP + PM_L2_SYS_PUMP) * 10015.3 Event GroupsThese events are listed in Two event groups are needed to cover memory location events.Table 15-1. The relevant events are listed alphabetically by name and each row includes the name of a PMCgroup where the event can be found and a short description. The PMC group can be used with tools likehpmcount (see Section 4.2.1) to collect several events at once, minimizing the number of runs needed tocollect a complete set of data. Events can be used with perf (see Section 5.1), oprofile (see Section 5.2) ortprof (see Section 4.3)Two event groups are needed to cover memory location events.Table 15-1 L2 read-claim machine events with their corresponding event groups and brief descriptionEvent Name Group Name Event DescriptionPM_L2_NODE_PUMPpm_l2_misc5RC req that was a local (akanode) pump attemptPM_L2_SYS_PUMPpm_l2_misc3RC req that was a global (akasystem) pump attemptCopyright ©2011 IBM Corporation Page 46 of 52