Late 2013 iMac 21.5' running very slow

Everything is too slow....

Xcode build project is too slow.

app is stuck when using magic trackpad go to previous page ( etc Xcode, Safari... )

About my mac :

The snapshot for CPU / Memory / Disk monitor :

The EtreCheck report :

EtreCheck version: 2.9.12 (265)

Report generated 2016-05-06 10:11:49

Download EtreCheck from https://etrecheck.com

Runtime 13:48

Performance: Poor

Click the [Support] links for help with non-Apple products.

Click the [Details] links for more information about that line.

Problem: Computer is too slow

Hardware Information: ⓘ

iMac (21.5-inch, Late 2013)

[Technical Specifications] - [User Guide] - [Warranty & Service]

iMac - model: iMac14,1

1 2.7 GHz Intel Core i5 CPU: 4-core

8 GB RAM Upgradeable - [Instructions]

BANK 0/DIMM0

4 GB DDR3 1600 MHz ok

BANK 1/DIMM0

4 GB DDR3 1600 MHz ok

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n/ac

Video Information: ⓘ

Intel Iris Pro

System Software: ⓘ

OS X El Capitan 10.11.4 (15E65) - Time since boot: about 11 days

Disk Information: ⓘ

APPLE HDD HTS541010A9E662 disk0 : (1 TB) (Rotational)

EFI (disk0s1) <not mounted> : 210 MB

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB

Macintosh HD (disk1) / : 999.03 GB (795.52 GB free)

Core Storage: disk0s2 999.35 GB Online

USB Information: ⓘ

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. FaceTime HD Camera (Built-in)

Apple Inc. iPhone

Thunderbolt Information: ⓘ

Apple Inc. thunderbolt_bus

Configuration files: ⓘ

System Integrity Protection status: disabled

Gatekeeper: ⓘ

Anywhere

Kernel Extensions: ⓘ

/Library/Application Support/org.pqrs/Karabiner

[loaded] org.pqrs.driver.Karabiner (10.18.0 - SDK 10.11 - 2016-03-07) [Support]

/Library/Application Support/org.pqrs/Seil

[loaded] org.pqrs.driver.Seil (12.0.0 - SDK 10.11 - 2015-12-05) [Support]

System Launch Agents: ⓘ

[not loaded] 8 Apple tasks

[loaded] 141 Apple tasks

[running] 75 Apple tasks

[killed] 14 Apple tasks

14 processes killed due to insufficient RAM

System Launch Daemons: ⓘ

[not loaded] 42 Apple tasks

[loaded] 143 Apple tasks

[running] 90 Apple tasks

[killed] 14 Apple tasks

14 processes killed due to insufficient RAM

Launch Agents: ⓘ

[loaded] org.macosforge.xquartz.startx.plist (2015-10-16) [Support]

[loaded] org.tigris.scplugin.launch.plist (2010-02-18) [Support]

Launch Daemons: ⓘ

[loaded] com.adobe.fpsaud.plist (2016-04-16) [Support]

[running] com.apple.serverd.plist

[running] com.apple.xcscontrol.plist

[running] com.apple.xcscouch.plist

[running] com.apple.xcsd.plist

[running] com.apple.xcsd.worker.plist

[running] com.apple.xcsnginx.plist

[running] com.apple.xcsredis.plist

[loaded] org.macosforge.xquartz.privileged_startx.plist (2015-10-16) [Support]

[not loaded] org.pqrs.Karabiner.load.plist (2016-03-07) [Support]

[not loaded] org.pqrs.Seil.load.plist (2015-12-05) [Support]

[loaded] org.wireshark.ChmodBPF.plist (2016-04-25) [Support]

User Launch Agents: ⓘ

[loaded] com.apple.serveralertproxy.plist

[loaded] com.google.keystone.agent.plist (2016-03-03) [Support]

[running] com.spotify.webhelper.plist (2016-04-25) [Support]

[running] com.w0lf.cDock.plist (2015-11-12) [Support]

User Login Items: ⓘ

iTunesHelper 應用程式 (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

Flux 應用程式 (/Applications/Flux.app)

Spotify 應用程式 Hidden (/Applications/Spotify.app)

Spotifree 應用程式 Hidden (/Applications/Spotifree.app)

ClipMenu 應用程式 (/Applications/ClipMenu.app)

Near Lock 應用程式 (/Applications/Near Lock.app)

Alfred 2 應用程式 (/Applications/Alfred 2.app)

Karabiner 應用程式 Hidden (/Applications/Karabiner.app)

Seil 應用程式 (/Applications/Seil.app)

Other Apps: ⓘ

[running] com.etresoft.EtreCheck.1010592

[running] com.github.norio-nomura.SIMBL-Agent.62432

[running] com.googlecode.iterm2.58272

[running] com.hegenberg.BTTRelaunch.70752

[running] com.naotaka.ClipMenu.47392

[running] com.runningwithcrayons.Alfred-2.251872

[running] com.sublimetext.2.50592

[running] com.syntevo.smartsvn.550752

[running] jp.naver.line.mac.243232

[running] me.nearlock.Near-Lock.224672

[loaded] org.calendarserver.agent

[loaded] org.calendarserver.archive

[loaded] org.calendarserver.relocate

[running] org.herf.Flux.6112

[loaded] org.postfix.master.passive

[running] org.pqrs.Karabiner.48352

[running] org.pqrs.Seil.252512

[loaded] 507 Apple tasks

[running] 236 Apple tasks

[killed] 32 Apple tasks

Internet Plug-ins: ⓘ

FlashPlayer-10.6: 21.0.0.226 - SDK 10.6 (2016-04-22) [Support]

QuickTime Plugin: 7.7.3 (2016-03-22)

Flash Player: 21.0.0.226 - SDK 10.6 (2016-04-22) [Support]

JavaAppletPlugin: 15.0.1 - SDK 10.11 (2015-12-16) Check version

Default Browser: 601 - SDK 10.11 (2016-03-22)

Safari Extensions: ⓘ

trans - willard (2015-12-14)

3rd Party Preference Panes: ⓘ

Flash Player (2016-04-16) [Support]

TeXDistPrefPane (2015-12-18) [Support]

Time Machine: ⓘ

Time Machine not configured!

Top Processes by CPU: ⓘ

10% bird

5% kernel_task

3% WindowServer

2% beam.smp

1% com.apple.WebKit.WebContent(12)

Top Processes by Memory: ⓘ

1023 MB kernel_task

844 MB com.apple.WebKit.WebContent(12)

647 MB Xcode

262 MB node(4)

221 MB Interface Builder Cocoa Touch Tool(8)

Virtual Memory Information: ⓘ

30 MB Free RAM

7.97 GB Used RAM (1.48 GB Cached)

905 MB Swap Used

Diagnostics Information: ⓘ

May 5, 2016, 02:12:32 PM ~/Library/Logs/DiagnosticReports/codesign_2016-05-05-141232_[redacted].crash

/usr/bin/codesign

May 4, 2016, 04:46:17 PM /Library/Logs/DiagnosticReports/Mail_2016-05-04-164617_[redacted].hang

/Applications/Mail.app/Contents/MacOS/Mail

May 4, 2016, 04:41:48 PM ~/Library/Logs/DiagnosticReports/Mail_2016-05-04-164148_[redacted].crash

May 3, 2016, 06:29:17 PM /Library/Logs/DiagnosticReports/Xcode_2016-05-03-182917_[redacted].cpu_resource .diag [Details]

/Applications/Xcode.app/Contents/MacOS/Xcode

Apr 12, 2016, 09:06:49 AM /Library/Logs/DiagnosticReports/Kernel_2016-04-12-090649_[redacted].panic [Details]

Apr 11, 2016, 06:02:53 PM /Library/Logs/DiagnosticReports/Kernel_2016-04-11-180253_[redacted].panic [Details]