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--- ram_diagnostics [2015/04/15 08:13] – created luke7858
+++ ram_diagnostics [2024/05/23 07:26] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+Command organises ps output by rss
+\\
+RSS stands for Resident Set Size
+\\
+This is a actual number in kilobytes of how much RAM the current process is using.
 <sxh bash>
 ps -Fe --sort:-rss
@@ Line 6: / Line 11: @@
 ps -Fe --sort:-rss | head -11
 </sxh>
+\\
+Find the ram usage of a specific service:
+<sxh bash>
+ps --no-headers -o "rss,cmd" -C httpd | awk '{ sum+=$1 }
+END { printf ("\nRAM statistics\n--------------\n") }
+END { printf ("Total RAM:           %d%s\n", sum/1024, "M") }
+END { printf ("Total processes:     %d\n", NR) }
+END { printf ("Average RAM/process: %d%s\n", sum/NR/1024, "M\n") }'
+</sxh>
+\\
+\\
+Description
+<sxh bash>
+-e = select all processes
+-F = full format
+--sort:-rss = sort the results by resident set size (real memory size in bytes)
+</sxh>
+\\
+\\
+Once you have the output of the command you will need to investigate the processes 'State'
+^ State ^ Definition ^
+| D  | uninterruptible sleep (usually IO) |
+| R  | running or runnable (on run queue) |
+| S  | interruptible sleep (waiting for an event to complete) |
+| T  | stopped, either by a job control signal or because it is being traced |
+| X  | dead (should never be seen) |
+| Z  | defunct ("zombie") process, terminated but not reaped by its parent |
+|    | |
+| <  | high-priority (not nice to other users) |
+| N  | low-priority (nice to other users) |
+| L  | has pages locked into memory (for real-time and custom IO) |
+| s  | is a session leader |
+| l  | is multi-threaded (using CLONE_THREAD, like NPTL pthreads do) |
+| +  | is in the foreground process group |