top is a Unix/Linux/BSD program to show what processing are running. It can show the top users of CPU or memory.

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34
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5answers
13k views

How to understand the memory usage and load average in linux server

I am using a linux server which has 128GB of memory and 24 cores. I use top to see how much it is used. Its output is pasted at the end of the post. Here are two questions: (1) I see that each of the ...
22
votes
3answers
16k views

Linux - How can I see what's waiting for disk IO

I have a server that has a really high load. Nothing is jumping out at me in terms of CPU usage, and it's not swapping. I think it's cause some processes are waiting for disk IO, and I want to see ...
14
votes
1answer
11k views

How to interpret output from Linux 'top' command?

Following a discussion made HERE about how PHP-FPM consuming memory, I just found a problem in reading the memory in top command. Here is a screenshot of my top just after restarting PHP-FPM. ...
92
votes
2answers
39k views

What exactly do the colors in htop status bars mean?

By default, htop shows colored status bars for processors, memory, and swap. From left to right, the bars are colored green, blue, yellow, and red depending on some thresholds. What does it mean when ...
5
votes
4answers
621 views

Memory Usage in LINUX

I have a debian system. It has 8GB memory. When I do top it shows 7.9 GB memory used and rest free. I add up the memory usage of all the programs running from top and they hardly sum up to around 50 ...
3
votes
1answer
439 views

Measuring load - %CPU in top is different than %us

When I run TOP on a remote server, I see a very small system utilization (3.8%us). However, for the actual process I am seeing 29.6% of the CPU. Since this server has 8 CPU cores, is the %CPU the ...
12
votes
2answers
4k views

How is memory usage reported in Linux?

Using ps, I can see the size, the vsize (same as top's VIRT?), and the rss (same as top's RES?). (One more I see in top is SHR.) Could someone summarize for me what these different fields mean?
6
votes
1answer
2k views

Why does top report a different cpu usage than CloudWatch?

top shows an average CPU usage during peak times of about 20% while CloudWatch monitoring shows an average CPU usage of 40%. What causes this discrepancy?
11
votes
3answers
7k views

What does %st mean in top?

Here is an example from my top: Cpu(s): 6.0%us, 3.0%sy, 0.0%ni, 78.7%id, 0.0%wa, 0.0%hi, 0.3%si, 12.0%st I am trying to figure out the significance of the %st field. I read that it means ...
2
votes
2answers
2k views

How do get apache display url request in Top and PS?

Is there a way to get apache to display the url that it is handling in top and ps? This would help us nail down performance issues much more faster. Thanks.
1
vote
4answers
2k views

Apache uses up a lot of CPU for small website

I have a CentOS 5.5 VPS server with 512MB RAM setup. There is 1 website hosted on it through Apache/PHP/MySQL which is built in Magento, a popular ecommerce framework. When I browse the website, it ...
4
votes
1answer
2k views

MongoDB virtual memory usage

I'm testing MongoDB for archives data. We have a collection with 160M rows. MongoDB instance takes 76.2 Gb virtual memory on a 12 Gb physical memory box ;-) The swap in null. I read that virtual ...
2
votes
4answers
2k views

Linux high memory usage (top total mismatch)

I havea poor mans vps - 256MB dedicated RAM. I have installed LAMP. No website is currently UP on the server yet. The memory usage is still 225MB (only 31 MB free). I have measured using top and ...
0
votes
2answers
237 views

How to clear/reset the top-commands TIME counter

To find a performance problem I use "top" commands TIME column in cumulative mode (which is important for me because it also captures all the small executed child processes) When any changes in the ...
0
votes
2answers
263 views

How Can Linux Top Show 2% Idle, but Load Say 1.20?

On CentOS5, I'm seeing the 'top' command showing a hover between 20% and 2% idle, but then the load says 1.20. How can that be possible? When I type 'uptime', as well, I see 3 load numbers that are ...
14
votes
6answers
30k views

wa (Waiting for I/O) from top command is big

I have a forum with a lot of visitors, Some days the load increase to reach 40 without increase of the number vistors. As you can see from the below output, the waiting time is high (57%). how do I ...
10
votes
5answers
5k views

Confused by CPU values in Unix 'top' command

In the screenshot below, the overall CPU is being reported as 3% but the mysqld process is reported as using 57%. Is this 57% of the overall 3% and thus mysqld is only using about 1.5% of the CPU? ...
5
votes
2answers
630 views

Load Average above 20 for single core vps on debian

OS: Debian 6.0 RAM:3072 M, CPU:single core. top: top - 08:56:43 up 21 days, 12:37, 1 user, load average: 28.38, 22.48, 15.95 Tasks: 8 total, 1 running, 7 sleeping, 0 stopped, 0 zombie ...
3
votes
2answers
2k views

Why does ec2 monitoring show 100% cpu and top only 20%?

I am running an python script on an ec2 instance that inserts rows in an database on another instance. In ec2's monitoring I saw a 100% cpu utilization, whereas top only shows 20% for the python ...
2
votes
1answer
544 views

top, w, ps showing wrong CPU times

I've spotted this trait recently on some of my Ubuntu servers (10.04.2) on Amazon EC2 (not noticed this on any physical boxes), and can't quite comprehend how it's getting these figures. They can't be ...
2
votes
5answers
788 views

%CPU for a process

Looking at the output of top on our server, one of my colleagues told me that the fact that some processes got less than 100 "%CPU" was because I was running too many processes. He added that based on ...
1
vote
2answers
1k views

memory leak? RHEL 5.5. RSS show ok, almost no free memory left, swap used heavily

i encounter a very instresting problem, and it seems that some physical may disapper quietly. i am very puzzled, so if anyone could give some help, I would be very appreciated. here is my top show: ...
0
votes
1answer
715 views

memory difference on top and htop

I got a new VPS as my database server. I installed only mysql and started. After some time(even after shutting down mysql service), I see only %3-4 of the memory used in htop but according to top I ...
4
votes
3answers
124 views

On a freshly-rebooted server why would the CPU running time of processes be huge?

I rebooted our server this morning, yet there are umpteen processes that appear to have been running for 600+ days? Could someone please shed some light? The datetime of the machine is correct: ...
2
votes
3answers
3k views

Diagnosing high CPU waiting

I have a monitoring server that is running icinga/collectd/graphite with about 50 hosts. I have noticed high load/slugging performance on the box. If you take a look at top, you'll see: Cpu(s): ...
1
vote
1answer
587 views

How to get /proc/[pid]/cmdline to contain command arguments?

I am running into an issue where some of my Ubuntu/Debian servers do not show the arguments passed to rake in either top or ps. I have tracked this problem down to a variation in output given by ...
1
vote
3answers
1k views

No apparent reason for high load average

We have several web servers running on Amazon (ec2) c1.xlarge, over Amazon AMI. The servers are duplicates of each other, running the exact same hardware and software. Each server spec is: 7 GB of ...
0
votes
2answers
1k views

how to monitor select processes on centos 5.x host?

I would like to monitor a select group of processes, vmware vm's, running on my centos 6 host. "top" gives me most of what I want in that I can use -p to specify only those processes and -c to get ...