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, rsc -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
