MS Options— Advanced

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7.4.1.5 MS Options— Advanced

These settings can help optimize your memory usage, especially for large MSs. A rule of thumb is that they can be increased until response becomes sluggish, when they should be backed down again.

You can run the unix ’top’ program and hit ’M’ in it (to sort by memory usage) in order to examine the effects of these settings. Look at the amount of RSS (main memory) and SWAP used by the X server and ’casaviewer’ processes. If that sounds familiar and easy, then fiddling with these settings is for you. Otherwise, the default settings should provide reasonable performance in most cases.

Cache size
The value of this option specifies the maximum number of different views of the data to save so that they can be redrawn quickly. If you run an animation or scroll around zoomed data, you will notice that the data displays noticeably faster the second time through because of this feature. Often, setting this value to the number of animation frames is ideal Note, however, that on multi-panel displays, each panel counts as one cached image.
Large images naturally take more room than small ones. The memory used for these images will show up in the X server process. If you need more Visibility Memory (below) for a really large ms, it is usually better to forgo caching a large number of views.
Max. Visibility Memory
This option specifies how many megabytes of memory may be used to store visibility data from the measurement set internally. Even if you do not adjust this entry, it is useful to look at it to see how many megabytes are required to store your entire (selected) MS in memory. If the slider setting is above this, the whole selected MS will fit into the memory buffer. Otherwise, some data planes will be ’grayed out’ (see Apply Button, § 7.4.1.6 below), and the selected data will have to be viewed one buffer at a time, which is somewhat less convenient. In most cases, this means you should select fewer fields or spectral windows – see § 7.4.1.2. The ’casaviewer’ process contains this buffer memory (it contains the entire viewer, but the memory buffer can take most of the space).

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