Messages in this thread | | | From | Albert Cahalan <> | Subject | Re: CONFIG_RANDOM (compromise?) | Date | Sun, 26 May 1996 17:21:50 -0400 (EDT) |
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> From: Lauri Tischler <ltischler@fipower.fi>
>>>> There's also an argument that the random number generator causes >>>> unnecessary overhead for people who never use it, and should therefore >>>> be made an option. However, I have not yet seen anyone post >>>> benchmarks or any other form of statistic which might demonstrate that >>>> such overhead exists.
Someone posted loss of about 5% for read performance.
>>> all right then. I really have no need for /dev/random. Anyone else ? >>> >> Personaly I have no need for it too. >> > If we go on dropping off useless stuff there are a _lot_ of candidates > from me... > - dec alpha stuff > - mips stuff > - amiga stuff > - ide disks > - all cdroms exept scsi > - ftape > I DONT NEED THEM so ergo they are useless. :)
You are right. When you run 'make config', choose 'N' to keep all that extra code out of your kernel. That's what I do. Unfortunately, people are stuck with /dev/random because there is no config option.
/dev/random is less useful than /proc and IPC, both of which are options. Any argument you can make for requiring /dev/random applies to IPC and even more so to /proc. What is /dev/random used for? Why, it is unswappable kernel code that generates complete garbage at the expense of reduced disk performance...
Next: It might be desirable to collect random events in the kernel. It is _not_ desirable to store and mix them with a complicated hash function in the kernel. Put it in a library. If you think you will need your random data in bursts now and then, have a daemon collect and serve the random data. The daemon could collect many megabytes of data on a spare disk. Maybe a daemon that is suid root (keep /dev/whatever mode 600) which anyone can start when random data is required. That way the daemon can die after a period of disuse and be restarted later.
Does anyone else think the kernel has too many checksum/CRC/hash functions? We need one for Elf, one(?) for networking, and one for ftape. The decompression code does not need its own CRC. Neither does the /dev/random.
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