Re: [U-Boot] JFFS2 with NAND flash is very SLOW ...
On Tuesday 02 June 2009 15:23:57 Pierre Savary wrote:
Is it better to use or not D-cache and I-cache?
Depends a bit on the "application". From my experience I-Cache is most important. But for memory intensive applications (JFFS2 might be such a beast) D-cache could be very helpful as well. Best is to have both enabled of course.
Currently, in my config file, I have only #define CONFIG_CMD_CACHE What do I have to add?
Defining the cache commands doesn't insure that caches are really enabled. Some platforms don't support I- and/or D-cache in U-Boot. I can only speak for PPC4xx which has I-cache enabled and "usually" D-cache disabled (because of cache-coherency issues). This might be different on your platform. Again, just enabling the cache commands will most likely not help here.
Best regards, Stefan
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In fact it is not better with this config: #define CONFIG_ICACHE_ON #define CONFIG_DCACHE_ON #define CONFIG_SYS_DCACHE_SIZE 32768 #define CONFIG_SYS_ICACHE_SIZE 32768 #define CONFIG_SYS_CACHELINE_SIZE 32
My architecture is arm926ejs and it seems that CACHE management is not implemented...
I just measure a load of uImage (2MB) ... it takes more than 2 minutes :-(
Pierre
-----Message d'origine----- De : u-boot-bounces@lists.denx.de [mailto:u-boot-bounces@lists.denx.de] De la part de Stefan Roese Envoyé : mardi 2 juin 2009 15:32 À : u-boot@lists.denx.de Cc : Pierre Savary; 'Cote, Sylvain' Objet : Re: [U-Boot] JFFS2 with NAND flash is very SLOW ...
On Tuesday 02 June 2009 15:23:57 Pierre Savary wrote:
Is it better to use or not D-cache and I-cache?
Depends a bit on the "application". From my experience I-Cache is most important. But for memory intensive applications (JFFS2 might be such a beast) D-cache could be very helpful as well. Best is to have both enabled of course.
Currently, in my config file, I have only #define CONFIG_CMD_CACHE What do I have to add?
Defining the cache commands doesn't insure that caches are really enabled. Some platforms don't support I- and/or D-cache in U-Boot. I can only speak for PPC4xx which has I-cache enabled and "usually" D-cache disabled (because of cache-coherency issues). This might be different on your platform. Again, just enabling the cache commands will most likely not help here.
Best regards, Stefan
===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
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