PROFILING & OPTIMIZATIONTools, guidelines, and techniques

PERFORMANCE

WHY BOTHER?

HIGHER CONVERSION RATES

SLOW MOBILE CONNECTIONS

CONSERVE CAPACITY

RULES; MORE LIKE GUIDELINES

Guideline

MEASURE EVERYTHING

Guideline

HUNT THE BIG FISH

Guideline

START CHEAP & ITERATE

Cost Order

Minify assets

Compress images

Reduce the number of HTTP requests

Optimize database queries

Add caching

Code optimization

JUNK UP FRONT

Junk Up Front

MeasuringChrome developer tools

Junk up front

Number of requests

Number of hosts

Image count & image size

Script count & script size

Fixing

Smushit (pngcrush, jpegtran, imagemagick)

Uglify.js, CSSMin

Make, phing, rake, grunt, shell scripts

Image sprites

Guideline

AVOID WORK TO GO FASTER

WEBSERVER TRICKS

MeasuringChrome developer tools

Webserver tricks

GZIP all the things.

Far Future cache headers.

Consider a CDN.

SQL MOLASSES

Database slowness

Many backend performance issues are caused by too many, or slow queries.

Mysql has a pretty terrible query planner.

Sub-queries and derived table joins will eventually catch fire.

Slow query logs, mtop, or monitoring like new relic are your best friend.

Database slowness

Slow query logs - Percona makes great tools for MySQL.

Disable query caching.

Run EXPLAIN on slow queries.

Add indexes/tweak queries, and repeat.

Explain QueriesVisual explain makes it easier.

Indexes

Index commonly used columns.

Column order in matters in indexes.

CACHING

Caching

Can be expensive to rollout, if you need new infrastructure

Cache expiration is really really hard.

What to Cache

Results that don’t change often

Use monitoring/analytics to find the busiest pages.

Start using caching there.

Expand once you’ve learned more.

Where to cache

Hopefully in Memcache/Redis

Failing that in Apc/Wincache

Files - Sometimes not faster.

Optimize cache use

Watch cache miss rate.

Tune cache expiration so you miss less often.

Guideline

OPTIMIZE CODE LAST, MOST OF THE TIME

JAVASCRIPT

PHP

Javascript tools

Chrome dev tools are the gold standard.

CPU profiles are invaluable.

Heap comparisons can be used to find memory leaks.

Cpu ProfilerChrome dev tools

Cpu ProfilerChrome dev tools

Cpu ProfilerChrome dev tools

Cpu ProfilerChrome dev tools

PHP TOOLS

Debug KitDeeper insights into CakePHP

XHProf

PECL extension produced by Facebook.

Captures runtime metrics at a function level.

Possible to use in a sub-sample of production unlike xdebug.

XhguiNicer UI to XHProf data

XhguiNicer UI to XHProf data

XDebug

Not suitable for servers with traffic,

Very detailed results.

WebgrindXDebug UI

Other PHP tweaks

Opcode caching is a must.

Don’t use file based sessions.

RECAP

MEASURE EVERYTHING

BE THRIFTY

START IN THE FRONT

AVOID WORK

OPTIMIZE CODE

THANKS