reporting and analysis of ibm’s cpu measurement facility data philadelphia cmg september 14, 2012...
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Reporting and Analysis of IBM’sCPU Measurement Facility Data
Philadelphia CMGSeptember 14, 2012
Bill SheldenBill.Shelden@PerfTechPro.com
• Introduction• CPU Measurement Facility• Using the SMF 113 records
• Data from a 2097-706 (z10)• Relative Nest Intensity• Matching LSPR Workloads (LOW, AVG, HIGH)
• Data from a 2818-Y02 (z114)• MIPS Reasonability Check• CPU Capacity Planning Checklist• Conclusions• PerfTechPro Offer
Topics
• CPU MF - 2012 Update and WSC Experiences for SHARE Atlanta Final.pdf
• CPU MF Webinar Part 1 May 2 Final.pdf• CPU MF Webinar Part 2 June 14 Final.pdf• Peter.Enrico.Exploring.SMF113.and.CPU.Counters.pdf• SA23-2260-02 The Load-Program-Parameter and the
CPU-Measurement Facilities.pdf• SA23-2261-01 IBM The CPU-Measurement Facility
Extended Counters Definition for z10 and z196.pdf
References
• Introduced in z10 and later processors • New facility that provides hardware instrumentation data for production
systems• Two Major components
• Counters• Cache and memory hierarchy information • SCPs supported include z/OS and z/VM
• Sampling• Instruction time-in-CSECT
• New z/OS HIS started task• Gathered on an LPAR basis• Writes SMF 113 records
• New z/VM Monitor Records• Gathered on an LPAR basis – all guests are aggregated• Writes new Domain 5 (Processor) Record 13 (CPU MF Counters) records
• Minimal overhead
Introduction - CPU Measurement Facility
• Counters are cumulative• Need to compute deltas between records
• Cut on the SMF accounting interval• Not the RMF interval
• Records pertain to a specific LPAR
Introduction – Using the SMF113 records
Data from a 2097-706 (z10)
Cycles Per Instruction
Level 1 Miss %
% of L1 Misses Sourced from Memory
Instruction Sourcing Profile (of L1 Misses)
Relative Nest Intensity
• Some Definitions:• L2LP = % from Level 2 Local cache (same book)• L2RP = % from Level 2 Remote cache (different book)• L3P = % from Level 3 cache• L4LP = % from Level 5 Local cache (same book)• L4RP = % from Level 4 Remote cache (different book) • MEMP = % sourced from Memory
• RNI - Reflects the distribution and latency of sourcing from shared caches and memory• For z10 EC and BC:
• RNI = (1.0*L2LP + 2.4*L2RP + 7.5*MEMP) / 100 • For z196 / z114:
• RNI = 1.6*(0.4*L3P + 1.0*L4LP + 2.4*L4RP + 7.5*MEMP) / 100
Relative Nest Intensity
L1MP < 3% RNI>0.75 AVERAGERNI<0.75 LOW
3%<L1MP<6% RNI>1.0 HIGH0.6<RNI<1.0 AVERAGERNI<0.6 LOW
L1MP>6% RNI>0.75 HIGHRNI<0.75 AVERAGE
RNI-based LSPR Workload Decision Table
Matching LSPR Workloads (LOW, AVG, HIGH)
Data from a 2818-Y02 (z114)
Cycles Per Instruction
Level 1 Miss %
% of L1 Misses Sourced from Memory
Instruction Sourcing Profile (of L1 Misses)
Matching LSPR Workloads (LOW, AVG, HIGH)
RNI may be Load dependent
0:291:29
2:293:29
4:295:29
6:297:29
8:299:29
10:2911:29
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Relative Nest IntensitiesSYSB (2818-Y02) SYSA (2097-706)
0:001:30
3:004:30
6:007:30
9:0010:30
12:0013:30
15:0016:30
18:0019:30
21:0022:30
0
200
400
600
800
1000
1200
MIPS UsedSYSB (2818-Y02) SYSA (2097-706)
Relative Nest Intensity
MIPS Reasonability Check
• From CPU Table (LOW RNI)• GPP ‘MIPS’ = 5045.60• ‘MIPS’/GPP = 5045.60 / 6 = 841 ‘MIPS’/GPP
• For 9:59 AM which is a LOW RNI interval• 3.54 Cycles per Instruction• 4.4 Cycles per nanosecond (per GPP)• 4.4 / 3.54 = 1.24 Instructions per Nanosecond• 1.24 x 1,000,000,000 Instructions per Second• 1.24 x 1000 = 1240 MIPS/GPP
MIPS Reasonability Check
• Collect CPU Measurement Facility Data for all ‘important’ LPARs
• For each LPAR:• Determine RNI-based LSPR workload mix
among LOW, AVG or HIGH• Determine MIPS values for current and
contemplated CPUs based on RITRs for RNI-based LSPR workload mix just determined• Use IBM’s zPCR to account for specific LPAR
configuration
CPU Capacity Planning Checklist
• Great insights into hardware and workload relationship
• RNI May be load dependent• More accurate CPU capacity planning
Conclusions
• Send us some of your data:• 24 hours of data• RMF 70, 71, 72, 73, and 75s• SMF 113s from one LPAR
• We will:• Return a set of charts in a PDF• Discuss your results on a WebEx
• Contact Bill Hart at bill.hart@perftechpro.com
PerfTechPro Offer
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