Hardware Reference
In-Depth Information
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 95416 kB
Committed_AS: 57876 kB
VmallocTotal: 188416 kB
VmallocUsed: 704 kB
VmallocChunk: 186852 kB
Many of these values are noticeably smaller.
In the sections that follow, a Model B to Model A comparison is provided. In some
cases, the comparison isn't meaningful because the values represent activity that has or
has not occurred. For example, the value for AnonPages is going to depend on the mix of
commands and applications that have run. But values from both models are provided for
completeness. Other values such as MemTotal can be meaningfully compared, however.
MemTotal
The
MemTotal
line indicates the total amount of memory available, minus a few reserved
binary regions. Note that memory allocated to the GPU is not factored into
MemTotal
.
Some may choose to allocate the minimum of 16 MB to the GPU to make more memory
available.
Model B
Model A
MemTotal
448,996 KB
190,836 KB
If we break this down a bit further, accounting for memory allocated to the GPU
(see Chapter 2 of
Raspberry Pi System Software Reference
[Apress, 2014] for more
details), we find that there is about 9.5 MB (1.9%) of memory that is unaccounted for, as
shown in Table
4-1
.
Table 4-1.
GPU and Main Memory Breakdown
Memory
Model B
Comments
MemTotal
448,996 KB
/proc/meminfo
gpu_mem
65,536 KB
/boot/config.txt
Total
514,532 KB
502.5 MB
Unaccounted for
9,756 KB
9.5 MB
