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Java Performance

Counter Monitor

JPCM - JDC12

Amr ElAdawy

JPCM

Agenda

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Software performance is

Better Performance tuning requires accurate Measurements.

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Software Performance

Software profiling tools tell you a lot bout memory,

But what about CPU?

CPU has three types of Cache:1. Data Cache2. Instructions Cache3. (TLB) Translation Lookaside Buffer

Smaller and faster memory that has a copy of data that is most frequently used.

Saves a lot of latency time consumed in accessing RAM.

Data Cache is leveled up to three layer (L1,L2,L3)....

CPU Cache

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CPU

RAM

Core1 Core2 Core3 Core4

L1 L1 L1 L1

L2 L2

L3

CPU Cache

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CPU Utilization(OS tools)

Shows the portion of time slots that the CPU scheduler in the OS could assign to execution of running programs or the OS itself

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Intel PCM & JPCMPCM is a C++ code from Intel to read data from PMU (Performance Monitoring Unit)

Supports Intel Xeon 5500, 5600, 7500, E7 and Core i7 processor

The following metrics are supported: Core:

1. Instructions retired2. Elapsed core clock ticks3. Core frequency.4. L2 cache hits and misses, L3 cache misses and hits.

Uncore:1. Read bytes from memory controller(s).2. Bytes written to memory controller(s).3. Data traffic transferred by the Intel® QuickPath Interconnect links

Get The CPU info CPU Family CPU Model Threads Per Core Number of Cores Number of Sockets

Get counter State Core Counter State Socket Counter State System Counter State

What can you do with JPCM?

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L2/L3 Metrics Cycles lost due to cache missesCache hitsCaches missesCache hit ratio

Other MetricsExecution usageTotal Execution usage CyclesInstructions retried

Around 24 metrics are exposed

What can you do with JPCM?

Come out with the CPU counters

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How it can be used?

Take a snapshot (Before)

Run your code

Take another snapshot

(After)

Native C++

JAVAJMX

JNI

PCM

Under the Hood!

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DEMO

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Thank You