Linux Performance Query Common directives

Category	Monitoring instructions	Describe	Note
Memory Bottleneck	Free	View Memory usage
Cpu Bottleneck	Top-hp	See the process with the highest CPU usage
	Vmstat 3 (interval time) 100 (number of monitors)	View Swap in/out location performance bottlenecks	Recommended Use
	PS-LP Process Number CU	To view the CPU consumption sort for a process
	Cat/proc/cpuinfo |grep ' Processor ' |wc-l	To view the number of CPU cores
	Top	View CPU overall consumption, Include sub-item consumption such as User,system,idle, Nice and other consumption	top show Java threads, then shift+m: by memory use to sort; shift+p: Span style= "font-family: Song body; Font-size:12px "> sort by CPU time; shift+t: cumulative by CPU use time sort multicore CPU, Press "1" to enter top view
Internet Bottleneck	Cat/var/log/messages	Check the kernel log to see if the packet is dropped
	Watch More/proc/net/dev	For locating drops, packet errors, To see network bottlenecks	Focus on drop (packet discarded) And the total amount of network packets delivered, Do not exceed the network limit
	Netstat-i	viewing network errors
	Ping IP	Test Network performance
Disk Bottleneck	Iostat-x-k-d 1	Disk IO read and write status	High, Span style= "font-family: Song body; Font-size:12px "> The first thing to check is machine Is there a lot of Span style= "font-family: Song body; FONT-SIZE:12PX "> Use swap space, Span style= "font-family: Song body; Font-size:12px "> is the CPU consumption is very large, If large description disk
	Iostat-x	View the read and write status of each disk in the system	Focus on await And Iowait's CPU share
	Iotop	See which process is reading IO in bulk	Generally first through Iostat To see if there is an IO bottleneck, Reposition which process is Bulk Read IO
	Df-hl	View disk space remaining
	Du-sh	View the current disk usage space
Application Bottleneck	Ps-ef|grep Java	To view the ID number of a process
	Ps-ef|grep java|wc-l	View the number of specific processes
	Netstat-tln|grep 8080	View Port Usage
	lsof-i:8080	See which process the port belongs to
	Cat ***.log | grep ***exception | Wc-l	Statistics log file contains the specific number of exceptions
	Jstack-l PID	Used to see if a thread has a deadlock
	Grep-v ' http/1.1″200′	Remove a URL that is not a 200 response code
	PS-EFL | grep [PID] | Wc-l	To view the number of threads created by a process
	Find/type f-name "*.log" |xargs grep "ERROR"	Count all the log files, Line containing the error character	This is troubleshooting. More useful in the process
	JSTAT-GC [PID]	View GC Status
	jstat-gcnew [PID]	Check out the memory usage of the young area, including MTT (maximum number of interactions is Is swapped to the old area), TT is the number of times that has been exchanged now
	Jstat-gcold	Viewing memory usage in the old area
	Jmap-j-d64-dump:format=b, File=dump.bin PID	Dump out Memory Snapshot	-j-d64 prevent Jmap from causing Virtual machine crash (Jdk6 bug)
	Xx:+heapdumponoutofmemeryerror	When Java is started, add the When a memory overflow occurs, the Storage Memory Snapshots
	Jmap-histo [PID]	Sort by object memory size	Note that it causes the full GC
 		memory snapshot of export complete	usual and jmap-permstat /opt/**/java Gcore.bin Use the core dump Convert to heap dump
 	- Xx:heapdumppath=/home/logs -xloggc:/home/log/ Gc.log -xx:+printgcdetails -xx:+printgcdatestamps	print GC log	 
	-server-xms4000m-xmx4000m -xmn1500m-xss256k -xx:permsize=340m-xx:maxpermsize=340m -xx:+useconcmarksweepgc	Sizing the JVM Heap	XSS is the stack size

Linux Performance Query Common directives