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Managing Memory Usage for Large Layout Files

It seems that no matter how much memory we equip our workstation with, we will need to open and display a GDSII or OASIS file that exceeds our available RAM. This application note attempts to describe how the user can set a couple of parameters that affect memory usage and the consequences on loading time and display performance.

Understanding the Scan/Load/Display Process

To appreciate how to tweak the load parameters, we need to understand how Qckvu3 uses memory to display the layout file. There are actually three critical steps:

how qckvu3 uses memory for display of GDSII

The Two Load Memory Parameters

There are two parameters the user can adjust to control the amount of RAM used.


Here are two examples used on a pair of Dual-Core AMD Opteron Processors 2.6GHz, running RHEL5, equipped with 32GB RAM.

Example1 - 32GB GDSII file

Items
per
Quad
Load GDSII
to
Memory?
Scan
Time
(mm:ss)
Load
Time
(mm:ss)
Total
S+L
(mm:ss)
Home
Display
(mm:ss)
Zoom Tight
Display
(mm:ss)
Total
Memory
GBytes
32 Yes 4:20 5:38 9:58 0:03 0:02 3.9

Example2 - 3.9GB GDSII file

Items
per
Quad
Load GDSII
to
Memory?
Scan
Time
(mm:ss)
Load
Time
(mm:ss)
Total
S+L
(mm:ss)
Home
Display
(mm:ss)
Zoom Tight
Display
(mm:ss)
Total
Memory
GBytes
32 Yes 0:26 0:25 0:51 0:02 0.00 0.7