top and htop provide real-time summary information about the set of
processes and threads currently running on the system and their resource
usage. Below is a brief summary of using and configuring top to show
different data, particularly in the context of using it for multi-threaded
processes. See the man
page for top for more information (it is super configurable).
cat /proc/cpuinfo cat /proc/cpuinfo | less # pipe cat's ouput to less (space to page fwd, q to quit) vim /proc/cpuinfo
If you run top with no command line options, then it displays per-process statistics. If you run top with -H, top will display statistics for individual threads (if you run the synch program for a large number of threads, you can see them show up in top):
top -Hhtop has a slightly different display of these data, and includes per-cpu summary data. You can also sort the data on different fields using the function key (F6). Try running htop and try sorting the output on different fields:
top -HWhile top is running, you can change what information it displays by typing f, and you should see something like this:
Fields Management for window 1:Def, whose current sort field is %CPU Navigate with Up/Dn, Right selects for move then <Enter> or Left commits, 'd' or <Space> toggles display, 's' sets sort. Use 'q' or <Esc> to end! * PID = Process Id * USER = Effective User Name * PR = Priority * NI = Nice Value * VIRT = Virtual Image (KiB) * RES = Resident Size (KiB) * SHR = Shared Memory (KiB) * S = Process Status * %CPU = CPU Usage * %MEM = Memory Usage (RES) * TIME+ = CPU Time, hundredths * COMMAND = Command Name/Line PPID = Parent Process pid UID = Effective User Id RUID = Real User Id ... P = Last Used Cpu (SMP) ... nsUTS = UTS namespace InodeThe starred items are the current values. To select different items or units for top to display, use arrow keys then type d or space. For example, to get top to print information about the last CPU each process or thread ran on, select the P option and hit return and the top window will now have a new column P that list this information.
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND 8249 newhall 20 0 153m 4488 472 R 47 0.0 0:02.78 6 gol 8250 newhall 20 0 153m 4488 472 R 47 0.0 0:02.76 2 gol 8236 newhall 20 0 153m 4488 472 R 46 0.0 0:02.77 6 gol 8237 newhall 20 0 153m 4488 472 S 46 0.0 0:02.77 4 gol 8243 newhall 20 0 153m 4488 472 R 46 0.0 0:02.76 1 gol 8239 newhall 20 0 153m 4488 472 S 46 0.0 0:02.76 7 gol 8240 newhall 20 0 153m 4488 472 R 46 0.0 0:02.76 5 gol 8244 newhall 20 0 153m 4488 472 R 46 0.0 0:02.72 2 gol 8251 newhall 20 0 153m 4488 472 R 46 0.0 0:02.78 4 golType q to exit top.