24
4.3 Fine-tuning ALICE
Memory Footprint
The amount of memory ALICE consumes depends on the
maximum image size to be processed, and the maximum
size of its internal image cache.
The image cache limit can be influenced by the
environment variable ALICE_MEM_FRACTION.
Its value is the percentage of the memory marked available to
the application by the operating system. Default is 0.25,
meaning that a quarter of the memory is the upper limit of
the image cache. Note that this is the image cache only,
not the total memory footprint of the application. The
environment variable can be set in
‘
c:\cshell\login.csh
‘.
Multi Threading
Besides running parallel to image loading and recording,
the image processing can operate multi-threaded to make
optimal use of the dual CPU system.
When running ALICE at the same time as recording on
the same host computer, multi-threading can be switched
off by setting ALIP_THREADS to 0.
This affects both ALICE as well as image processing for
recording. Setting ALIP_THREADS to 1 turns on multi-
threading, while setting it to “auto” causes the multi
threading to be turned on, but to be disabled it temporarily
if both ALICE and aldaemon are running at the same time,
to allow interactive working with ALICE while computing
data-intensive recordings. The auto setting is also the
default if the environment variable is not set. The
environment variable can be set in
‘
c:\cshell\login.csh
‘.
Configuration
4.3.
