Dear =?iso-8859-1?Q?Andreas_Bie=DFmann?=,
In message 8AE7E072-8389-49CA-B6C7-6C15C1877625@googlemail.com you wrote:
With your configuration, importing a 64 kB environment buffer would result in 32 k entries in the hash table.
Well therefore we have another 'algorithm' implemented to cope with this. The flag H_ALG_SMALL_BUF should be set especially when importing a small buffer. Anyhow the maximum limit some lines below will never be exceeded.
Well, you were talking about your defualt environment settings only. How big is the envrionment in your persistent storage (flash)? I bet it's at least several KB, resulting in thousands of entries in the hash table.
This obviously makes no sense.
I think we should rather make sure that a certain minimum of entries will always be available, for exmaple something like this:
int nent = 64 + size / 8;This sounds also good but why do not calculate as before and after that check some (maybe definable) borders?
How about: int nent = size / 8; if (nent < CONFIG_ENV_MIN_ENTRIES) nent = CONFIG_ENV_MIN_ENTRIES;
I cannot really proof it, but I am pretty much convinced that we should start with a non-zero constant and rather use a less steep increase.
Well in most cases the environment needs a static size. The actual size of environment has (in my view) no/small connection to space for environment in NV memory. In most cases the space reserved for environment is way to big cause of sector boundaries. Therefore I think
This is not true. Sector sizes affect only the CONFIG_ENV_SECT_SIZE settings, while the environment size is determined by CONFIG_ENV_SIZE which usually is MUCH smaller.
Example: "TQM5200.h":
#define CONFIG_ENV_SIZE 0x4000 /* 16 k - keep small for fast booting */ ... #define CONFIG_ENV_SECT_SIZE 0x40000
it would meet the needs when we have one (configurable) size for hash table without the calculation.
I disagree. Have a look at the "env import" and "env export" commands and think about what you can do with these - essentially they lift the fix connection to a pre-configured environment storage. Even if you have just 2 or 4 KiB environment settings in flash, you can now just load a file (over network, from USB stick or SDCard etc.) which may contain tons of commands and macro definitions.
Even if you don't have such usage in mind, I do not want to make this impossible by a too limited design.
Best regards,
Wolfgang Denk