Intel VTune Amplifier XE Overview

Transcription

1 Intel VTune Amplifier XE Overview June

2 Intel Parallel Studio XE 2011 Phase Productivity Tool Feature Benefit Advanced Build & Debug Intel Composer XE C/C++ and Fortran compilers, performance libraries,and parallel models Driving application performance and scalability benefits of multicoreand forward scale to manycore. Additionally providingcode robustness and security. Advanced Verify Intel Inspector XE Memory & threading error checking tool for higher code reliability & quality Increases productivity and lowers cost, by catching memory and threading defects early Advanced Tune Intel VTune TM Amplifier XE Performance Profiler to optimize performance and scalability Removes guesswork, saves time, makes it easier to find performance and scalability bottlenecks Combines ease of use with deeper insights. 11/22/2011 2

3 Available Tools and Tools Evolution Performance Analysis Tools + Intel VTune Amplifier XE Linux&Windows GUI/CLI support Tune Analyze and optimize performance issues PIN, Statistical Call Graph, Memory Checking, Other features, GUI Usability Some features will be incorporated into future mainstream products Mainstream Windows Visual Studio only 3

4 Intel Vtune Amplifier XE Integrates popular and mature features of Intel VTune Performance Analyzer, Intel Parallel Amplifier, Intel Thread Profiler and Intel Performance Tuning Utility But not a super-set in all cases Some additional features being worked on and will be added later; some are still being evaluated/might be added to future updates Standalone GUI on Linux* and Windows* GUI in all environments based on wxwidgets: Very fast and stable Same look-and-feel for Linux & Windows Fast and native implementation on Linux No sluggish and fragile emulations anymore!! Comprehensive Command Line interface New instrumentation technologies for data collection 4

5 Intel Vtune Amplifier XE Feature Highlights Ease of use is key focus Simple configuration of analysis session Copy and modify existing analysis types to adapt to special needs Intuitive filtering and display of data collected Stand-alone GUI but also seamless integration into Microsoft Visual Studio* on Windows* Extended Platform Coverage Windows* and Linux Microsoft*.NET* C# applications Advanced Source / Assembler View Analysis / event data mapped to the source / assembler code View and analyze assembler code as basic blocks 5

6 All available analysis types Different ways to start the analysis Helps creating new analysis types Copy the commandline to clipboard 6

7 Supported Analysis Techniques Hot Spot Analysis Where is the execution time spend? Includes statistical call graph Minimal intrusiveness due to statistical data collection Event Based Sampling (EBS): Where are architectural events like cache misses happening? Performance Event configuration Event grouping Thread Profiling Where is my concurrency poor and why? Which time do I spend in locks? Thread timeline visualizes thread activity and lock transitions Optional integrates EBS data collection and view 7

8 Data Collection Techniques EBS: Similar to Intel PTU, based on SEP (Sampling Enabling Platform Hotspot Analysis: User-mode sampling (aka stack sampling ) Concurrency Analysis: Dynamic binary instrumentation of PIN Only low-intrusive Probe-Mode ; slow JIT-Mode not used by performance tools Source modification/recompilation is not needed VTune Analyzer, PTU Parallel Amplifier Improved Event based sampling (PMU) PIN for Instrumentation, TBS for hotspot and stack sampling) Intel(R) VTune(TM) Amplifier XE 8

9 Hotspot Analysis For Hotspots analysis, only stack sampling is performed For each sample, capture execution context, time passed since previous sample and thread CPU time No specific filtering is done for Hotspots. The amount of data collected in Hotspots is rather moderate Screenshots are subject to change 9

10 Hotspot Analysis Summary View 10

11 Hotspot Result View incl. Timeline Callstack Threads Timeline 11

12 Parallelism/Concurrency Analysis For Parallelism / Concurrency analysis, Stack sampling is done just like in Hotspots analysis Wait functions are instrumented (e.g. WaitForSingleObject, EnterCriticalSection) Signal functions are instrumented (e.g. SetEvent, LeaveCriticalSection) I/O functions are instrumented (e.g. ReadFile, socket) 12

13 Parallelism/Concurrency Analysis Summary View 13

14 Parallelism/Concurrency Analysis 14

15 Event Based Sampling 15

16 Event Based Sampling Pre-defined event sets for supported processors Top level Triage Cache analysis and false sharing Branching issues Long-latency computation operations Structural hazards Working set size Data access patterns Memory latency Memory bandwidth Event multiplexing Pre-defined displays (viewpoints) transform data into information Numerous views, sophisticated filtering combining best we learned from EBS in Intel Vtune Perf. Analyzer and Intel PTU Cycle accounting analysis methodology 16 16

17 Introduction to Core architecture Execution Unit: Port Mapping Reservation station (36 entries) Port 0 Port 1 Port 5 Port 2 Port 3 Port 4 INT SIMD ALU 1 SHIFT 1 LEA SIALU 1 SISHIFT ALU 2 ALU 3 IMUL SHIFT 2 JEU SIMUL SIALU 2 SISHUF Resul lt Bus LOAD AGU LB STORE AGU SB 48 entries 32 entries DTLB STORE DATA (MIU) PMH MOB FMUL FADD FP FDIV FSHUF FPREM L1-D$ L2$/LL$ ROB

18 AnalysingExecution Unit Stage Divider as Sample The Divider is a big potential stall source Very high latency; almost no pipelining Event : DIV Counts the number of divide operations executed Event : RESOURCE_STALLS.DIV_BUSY Counts the number of cycles for which a micro-op stalls at issue due to div busy Try to find some useful work to do in parallel with divide operations Nehalem Penryn Core 2 Lat Through Latency Through Latency ency put put Through put DIVSD MULSD

19 Intel(R) VTune(TM) Amplifier XE Viewpoints and Groupings Groupings Each analysis types have pre-defined groupings Different groupings allow users analyze data in different ways with different focus in mind 19

20 Frame Analysis There are two ways to support frames and frame analysis Explicit frame marker by program APIs Recommend approach for version 1.0 Check out <Vtune Amplifier Install Dir>\include\ittnotify.h typedef struct itt_frame_t * itt_frame; itt_frame ITTAPI itt_frame_createa(const char *domain); itt_frame ITTAPI itt_frame_createw(const wchar_t *domain); void ITTAPI itt_frame_begin( itt_frame frame); void ITTAPI itt_frame_end ( itt_frame frame); Automated Frame detection using knowledge about graphic API (like DirectX) Prototype available; no final decision on whether it will make it to initial product release already 20

21 Frame Analysis using APIs itt_frame = itt_frame_createa("simdomain"); while(grunning) { itt_frame_begin(itt_frame); } start = clock(); //Wait all threads before moving into the next frame WaitForMultipleObjects(FUNCTIONAL_DOMAINS, esignal, TRUE, INFINITE); stop = clock(); //Give all threads the "go" signal for (int i = 0; i < FUNCTIONAL_DOMAINS; i++) SetEvent(bSignal[i]); if (frame % NETWORKCONNETION_FREQ == 0) { //Start network thread SetEvent(bNetSignal); } itt_frame_end(itt_frame); 21

22 Frame Analysis in GUI Frame boundaries 22

23 User Events Check out <Vtune Amplifier Install Dir>\include\ittnotify.h typedef int itt_event; itt_event LIBITTAPI itt_event_createa(const char *name, int namelen); itt_event LIBITTAPI itt_event_createw(const wchar_t *name, int namelen); int LIBITTAPI itt_event_start( itt_event event); int LIBITTAPI itt_event_end( itt_event event); DWORD WINAPI aiwork(lpvoid lparg) { int tid = *((int*)lparg); itt_event aievent; aievent = itt_event_createa("ai Thread Work",14); } while(grunning) { WaitForSingleObject(bSignal[tid], INFINITE); itt_event_start(aievent); dosomedataparallelwork(); itt_event_end(aievent); SetEvent(eSignal[tid]); } return 0; 23

24 User Events in GUI [1] User defined task User defined task User defined task 24

25 Intel(R) VTune(TM) Amplifier XE Command Line Interface Examples D:\Examples\>"c:\Program Files (x86)\intel\amplifier XE\bin32\amplxe-cl.exe" Command Line Tool Copyright (C) Intel Corporation. All rights reserved Usage amplxe-cl <-action-option> [-modifier-option] [[--] target [target options]] Where: action-option is one of the following: collect, collect-list, command, finalize, help, import, knob-list, report, report-list, version modifier-option is one or more of the following: allow-multiple-runs, callee-attribution-mode, csv-delimiter, cumulative-threshold-percent, data-limit, [no-]discard-raw-data, quiet, duration, filter, [no-]follow-child, format, group-by, knob, limit, mrte-mode, report-output, result-dir, resume-after, search-dir, start-paused, target-duration-type, target-pid, target-process, user-data-dir, verbose To view the results in the IDE, double-click the <resultname>.amplxe file located in the result directory. 25

26 Intel(R) VTune(TM) Amplifier XE Command Line Interface Examples Display a list of available analysis types and preset configuration levels amplxe-cl collect-list Run Hot Spot analysis on target myappand store result in default-named directory, such as r000hs inspxe-cl c hotspots-- myapp Run the Parallelism analysis, store the result in directory r001par amplxe-cl -c parallelism -result-dir r001par -- myapp 26

27 Intel(R) VTune(TM) Amplifier XE and Legacy Tools: Feature Comparison 27

28 Legacy Intel Vtune Performance Analyzer Features not yet (!!) available in current Version Performance Analysis for Java Support for Java will be added later Exact, graphical call graph Needed? 28

29 Intel Performance Tunining Utility (Intel PTU) Features not available in new Tool yet (!) Data Access Profiling Based on PEBS Precise Event Based Sampling Very likely added to future update Control-flow graph / basic block view Heap Memory ( Space-Time ) Profiling Very likely added to future update Call Count Analysis Similar to Precise Call Graph of VTunebut using PIN for instrumentation PTU available as a free, unsupported tool 29

30 More Wish-List Features Event Abstraction Architecture-independent tuning using events Hide specific processor-dependent details Improved support for parallel tasking models OpenMP* 3.0 tasking Intel Threading Building Blocks Intel Cilk Plus EBS for VMM/Virtual operating system environments 30

31 Intel PTU Basic block grouping and execution flow analysis

32 PTU Feature: Heap Profiling Spacetime Objects Number Call Stack Block Size Hot Path Allocation Graph

33 Summary Intel(R) VTune(TM) Amplifier XE is the next generation performance tool The new performance analysis tool is successor of popular Intel VTune + Thread Profiler Additional features and technologies New binary instrumentation engine Standalone GUI on Linux and Windows* Let us know about issues you see of course but also please submit feature requests Existing Intel Vtune Performance Analyzer license with non-expired support access will work for new tool 33