‘t’ command toggle.  They show an abbreviated summary consisting of these elements:
                      a    b     c    d
           %Cpu(s):  75.0/25.0  100[ ... ]

       Where:  a)  is the ‘user’ (us + ni) percentage; b) is the ‘system’ (sy + hi + si) percentage; c) is the total percentage; and d) is one of two visual graphs of those representations.  Such graphs also reflect separate
       ‘user’ and ‘system’ portions.

       If the ‘4’ command toggle is used to yield more than two cpus per line, results will be further abridged eliminating the a) and b) elements.  However, that information is still reflected in the graph  itself  assuming
       color is active or, if not, bars vs. blocks are being shown.

       See topic 4b. SUMMARY AREA Commands for additional information on the ‘t’ and ‘4’ command toggles.

   2c. MEMORY Usage
       This portion consists of two lines which may express values in kibibytes (KiB) through exbibytes (EiB) depending on the scaling factor enforced with the ‘E’ interactive command.

       As a default, Line 1 reflects physical memory, classified as:
           total, free, used and buff/cache

       Line 2 reflects mostly virtual memory, classified as:
           total, free, used and avail (which is physical memory)

       The  avail  number  on line 2 is an estimation of physical memory available for starting new applications, without swapping.  Unlike the free field, it attempts to account for readily reclaimable page cache and memory
       slabs.  It is available on kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as free.

       In the alternate memory display modes, two abbreviated summary lines are shown consisting of these elements:
                      a    b          c
           GiB Mem : 18.7/15.738   [ ... ]
           GiB Swap:  0.0/7.999    [ ... ]

       Where: a) is the percentage used; b) is the total available; and c) is one of two visual graphs of those representations.

       In the case of physical memory, the percentage represents the total minus the estimated avail noted above.  The ‘Mem’ graph itself is divided between the non‐cached  portion  of  used  and  any  remaining  memory  not
       otherwise accounted for by avail.  See topic 4b. SUMMARY AREA Commands and the ‘m’ command for additional information on that special 4‐way toggle.

       This table may help in interpreting the scaled values displayed:
           KiB = kibibyte = 1024 bytes
           MiB = mebibyte = 1024 KiB = 1,048,576 bytes
           GiB = gibibyte = 1024 MiB = 1,073,741,824 bytes
           TiB = tebibyte = 1024 GiB = 1,099,511,627,776 bytes
           PiB = pebibyte = 1024 TiB = 1,125,899,906,842,624 bytes
           EiB = exbibyte = 1024 PiB = 1,152,921,504,606,846,976 bytes

3. FIELDS / Columns
   3a. DESCRIPTIONS of Fields
       Listed below are top’s available process fields (columns).  They are shown in strict ascii alphabetical order.  You may customize their position and whether or not they are displayable with the ‘f’ (Fields Management)
       interactive command.

       Any field is selectable as the sort field, and you control whether they are sorted high‐to‐low or low‐to‐high.  For additional information on sort provisions see topic 4c. TASK AREA Commands, SORTING.

       The  fields  related  to  physical  memory  or  virtual memory reference ‘(KiB)’ which is the unsuffixed display mode.  Such fields may, however, be scaled from KiB through PiB.  That scaling is influenced via the ‘e’
       interactive command or established for startup through a build option.

       %CPU  --  CPU Usage
           The task’s share of the elapsed CPU time since the last screen update, expressed as a percentage of total CPU time.

           In a true SMP environment, if a process is multi‐threaded and top is not operating in Threads mode, amounts greater than 100% may be reported.  You toggle Threads mode with the ‘H’ interactive command.

           Also for multi‐processor