Caching for Cash: Benchmarking and Profiling

CACHING FOR CASH - BENCHMARKING Scott MacVicar + Helgi Þormar Þorbjörnsson php|works 2008

GOALS Learn how to ﬁnd slow pages Locate slow blocks of code Apply minor optimisations

THOUGHT STEPS Things seem a bit slow Take a guess whats slow Browse lots of code

SYSTEM COMPONENTS Appliation Server Database Server Application Database Network

PAGE BENCHMARKING Single Request doesn’t matter Average time for maximum amount of users Hopefully at worst it scales linearly

REQUIREMENTS Same hardware conﬁguration Same server conﬁguration Same network interface speed (100mbps) Basically your “staging server”

STEPS TO BENCHMARK Record server load Run our tests at least 3 times Take average of tests

BENCHMARKING TOOLS Apache Bench Apache Flood Siege

APACHE BENCH Shows requests per second Bundled with Apache Gives relative idea of load

APACHE BENCH - DEMO 1000 Requests with 5 at a time ab -n 1000 -c 5 http://localhost/phpBB3/index.php 1000 requests with 5 at a time using keep alive ab -n 1000 -c 5 -k http://localhost/phpBB3/index.php Output results to Excel / GNUPlot ab -n 1000 -c 5 -g http://localhost/phpBB3/index.php

ISSUES WITH APACHE BENCH Synthetic Benchmark No way to emulate users

APACHE FLOOD Proﬁle driven benchmarking XML Based conﬁg Use variables on pages

XML FORMAT URLLIST FARM FARMER PROFILE

URLIST Simple group of URLs Supports postdelay and predelay

FARMER Single User Can use URLLIST in various ways Random Order Round Robin Keep-Alive

FARM It’s where the farmers work Controls the way the farmers work Creates farmers too

PROFILE Runtime conﬁguration Can change various settings socket report

USE CASES User visits main page User visits main page then download page User visits main page then download and downloads a ﬁle

SINGLE PAGE Keep Alive Page Image Image

SINGLE PAGE XML

TWO PAGE VISITS Keep Alive Page Image Image 30 secs later Keep Alive Page Image Image

TWO PAGE VISITS XML

TWO PAGE VISITS AND DOWNOAD Keep Alive Page Image Image 30 secs later Keep Alive Page Image Image 15 secs later ISO

TWO PAGE VISIT AND DOWNOAD XML

SETUP A PROFILE enable keepalive use the relative times output format check for 200 OK

PROFILE XML

JOE THE FARMER

FARM FOR JOE TO WORK ON

RUNNING FLOOD flood <configuration.xml> > output.file anaylze-relative output.file

VMWARE INSTALL Run Run VMware- VMware- Run VMWare-fusion.dmg player-2.5.0-118166.exe Player-2.5.0-118166.i386 .bundle Reboot Copy Fedora 10 Folder to Disk Load via VMWare php / password

TASK • Visit http://localhost/phpBB3/ • View a forum after 20 seconds • View a thread after 5 seconds • Click reply after 60 seconds • Sample ﬁle in ﬂood-examples folder

SIEGE Provides functionality of Apache Bench and Flood Supports GET and POST with a simple syntax Benchmark and Internet mode

SIEGE COMMANDS 1000 Requests with 5 at a time siege -b -r 1000 -c 5 http://localhost/phpBB3/index.php 10 seconds with concurrency of 5 siege -b -c 5 -t 10 http://localhost/phpBB3/index.php Read urls.txt for a list of URLs siege -b -n 1000 -c 5

SPROXY Creates local socks proxy on your machine Set your browser to use the local proxy, port 9001 Browse your site with the actions you wish urls.txt is written with the POST and GET data

OTHER BENCHMARKING TOOLS JMeter httperf Web Application Stress Tool OpenWebLoad

PROFILING

WHAT IS PROFILING Examines the performance characteristics Records every function call Tracks execution time Tracks memory usage

PROFILING TOOLS XDebug apd

XDEBUG Debugger Code Coverage Memory and Executon time

XDEBUG PROTECTIONS Stack overﬂow in PHP Inﬁnite Recursion

ERROR MESSAGE HELPING

XDEBUG HELPFUL ERROR MESSAGES

MORE ERROR MESSAGE HELPING

EXECUTION TIME

MEMORY USAGE

EXECUTION TRACE xdebug.auto_trace=1 xdebug.trace_output_dir=/tmp xdebug.collect_params=1 xdebug.collect_return=1 xdebug.trace_output_name=trace.%c

EXECUTION TRACE

PARTIAL EXECUTION TRACE Tracing only parts of an application with xdebug_start_trace() and xdebug_stop_trace(). Fetching the trace ﬁle name that is being used with xdebug_get_traceﬁle_name(). Changing how much data is shown with xdebug.var_display_max_children, xdebug.var_display_max_data and xdebug.var_display_max_depth.

CODE COVERAGE Finds unexecuted code xdebug_start_code_coverage() xdebug_get_code_coverage() xdebug_stop_code_coverage()

CODE COVERAGE SAMPLE

CODE COVERAGE OUTPUT

PROFILING Execute action as normal in browser Outputs cachegrind file INI settings: xdebug.profiler_enable=1 ; enable profiler xdebug.profile_output_dir=/tmp ; output directory xdebug.profile_output_name=cachegrind.out.%p

PROFILING CONTINUED Locate parts of the code that is slow Work down tree to ﬁnd the slow sections Can it be cached? Can it be optimized? Occasionally built?

VIEWING PROFILE KCacheGrind MacCallGrind WinCacheGrind Carica CacheGrind

PROFILING DEMO

TASK sudo nano -w /etc/php.d/xdebug.ini remove ; from xdebug.profiler_enabled=1 Profile a page on Wordpress Profile a page on phpBB Try to find something slow you think could be improved 20 minutes

APD Lives in PECL Similar to XDebug Doesn’t require KCachegrind Still only PHP 4

APD apd_set_pprof_trace() to enable proﬁler pprof is a script to interpret the trace Outputs to apd.dumpdir

BRINGING IT TOGETHER Use proﬁler with benchmarks Proﬁling can be run on production sites Optimise slow code

RESOURCES Lunch - back at 1pm for Caching http://talks.macvicar.net/ http://httpd.apache.org/test/ﬂood/ http://xdebug.org/docs/ http://www.joedog.org

Caching for Cash: Benchmarking and Profiling

by Scott MacVicar on May 28, 2009

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