Messages in this thread |  | | Subject | Re: Since no one else has stepped forward: 'ZeroD' patch | From | Jes Degn Soerensen <> | Date | 09 Jan 1997 13:30:28 +0100 |
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>>>>> "Andi" == Andi Kleen <andi@mlm.extern.lrz-muenchen.de> writes:
Andi> Ingo Molnar <mingo@pc5829.hil.siemens.at> writes: >> Here is a patch that implements 'ZeroD', a simple kernel thread >> that uses up CPU idle time to keep a pool of pre-zeroed pages >> around. Almost anything that doesnt burn 100% CPU time all the time >> should benefit from this.
Andi> Hmm, did you check that this hasn't a bad effect on the cache Andi> memory when a cpu intensive process has to sleep for short Andi> times? A /proc/sys interface to tune it would be nice too.
I think you are on to something. I'm speaking mainly for the m68k port, as I don't know that much about x86 caches.
The idea of zerod may not be that good for cpus with relatively small caches and no cache write-through instructions such as the 68030 (the 68030 only has a 256 byte data cache and a 256 byte ins cache). On these cpus a clear-page() is enough to wipe out the entire data-cache ;( However for the 68040 and 68060, which got these nice move16 instructions that bypasses the cache, zerod will be fine.
Zerod may also be a bad idea for other small-cache architectures such as the sun4c - but I'm not sure about this, guess one of the Sparc hackers will be better to answer this one.
Therefore I think it might be a good idea to make zerod a config-option or at least an option to disable it?
Jes
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