Intel® 64 and IA-32 Architectures Optimization Reference Manual

USING PERFORMANCE MONITORING EVENTSMetricBus AccessesUnderway from theprocessor 2Bus Reads Underwayfrom the processor 2Table B-5. Performance Metrics - Bus (Contd.)DescriptionAccrued sum of thedurations of all bustransactions by thisprocessor.Divide by “BusAccesses from theprocessor” to get busrequest latency.Also beware ofdifferent recipes inmask bits for Pentium4 and Intel Xeonprocessors betweenCPUID model fieldvalue of 2 and modelvalue less than 2.Accrued sum of thedurations of all read(includes RFOs)transactions by thisprocessor.Divide by “Reads fromthe Processor” to getbus read requestlatency.Also beware ofdifferent recipes inmask bits for Pentium4 and Intel Xeonprocessors betweenCPUID model fieldvalue of 2 and modelvalue less than 2.Event Name or MetricExpressionIOQ_active_entriesIOQ_active_entriesEvent Mask ValueRequired1a. ReqA0, ALL_READ,ALL_WRITE, OWN,PREFETCH(CPUID model < 2);1b. ReqA0, ALL_READ,ALL_WRITE,MEM_WB, MEM_WT,MEM_WP, MEM_WC,MEM_UC, OWN,PREFETCH (CPUIDmodel >= 2).1a. ReqA0, ALL_READ,OWN, PREFETCH(CPUID model < 2);1b. ReqA0, ALL_READ,MEM_WB, MEM_WT,MEM_WP, MEM_WC,MEM_UC,OWN, PREFETCH(CPUID model >= 2);B-21