Messages in this thread | | | Date | Fri, 14 Aug 2009 23:15:00 +0200 | From | Robert Schwebel <> | Subject | Re: New fast(?)-boot results on ARM |
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On Fri, Aug 14, 2009 at 11:01:58PM +0200, Linus Walleij wrote: > >> > That's factor 70 away from the 110 ms boot time Tim has talked about > >> > some days ago (and he measured on an ARM cpu which had almost half > >> > the speed of this one), and I'm wondering what we can do to improve > >> > the boot time. > >> > >> 2.4s in uncompression? That seems like an obvious target for > >> improvement. > > > > Indeed, we'll check that. > > We got rid of uncompression on a flash-based system vastly improving > boot time. The reason is that compressed kernels are faster only when > the throughput to the persistent storage is lower than the decompression > throughput, and on typical embedded systems with DMA the throughput to > memory outperforms the CPU-based decompression. > > Of course it depends on a lot of stuff like performance of flash controller, > kernel storage filesystem performance, DMA controller performance, > cache architecture etc so it's individual per-system.
We have also done that on NOR based systems, but I'm not sure if it will work out for NAND as well.
Thanks,
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