[doc] install: be a bit clearer about calculating the ivshmem size

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Geoffrey McRae 2022-09-19 22:11:17 +10:00
parent 646a725c0e
commit 136410daac

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@ -70,9 +70,11 @@ Determining memory
You will need to adjust the memory size to be suitable for your desired maximum You will need to adjust the memory size to be suitable for your desired maximum
resolution, with the following formula: resolution, with the following formula:
``width x height x pixel size x 2 = total bytes`` ``width x height x pixel size x 2 = frame bytes``
``total bytes / 1024 / 1024 = total megabytes + 10`` ``total bytes / 1024 / 1024 = frame megabytes``
``total megabytes + 10 = total size required``
Where `pixel size` is 4 for 32-bit RGB (SDR) or 8 for 64-bit Where `pixel size` is 4 for 32-bit RGB (SDR) or 8 for 64-bit
(HDR :ref:`* <libvirt_determining_memory_hdr>`). (HDR :ref:`* <libvirt_determining_memory_hdr>`).
@ -85,7 +87,9 @@ For example, for a resolution of 1920x1080 (1080p):
``1920 x 1080 x 4 x 2 = 16,588,800 bytes`` ``1920 x 1080 x 4 x 2 = 16,588,800 bytes``
``16,588,800 / 1024 / 1024 = 15.82 MiB + 10 = 25.82 MiB`` ``16,588,800 / 1024 / 1024 = 15.82 MiB``
``15.82 MiB + 10 MiB = 25.82 MiB``
You must round this value up to the nearest power of two, which for the You must round this value up to the nearest power of two, which for the
provided example is 32 MiB. provided example is 32 MiB.