On Monday 18 September 2006 23:24, Jörn Engel wrote: > On Fri, 15 September 2006 22:44:07 +0200, Arnd Bergmann wrote: > > > > I'd guess that a 32 byte alignment is much better here, 64 byte sounds > > excessive. It should have the same effect with the current dentry layout > > and default config options, but would keep the d_iname length in the > > 16-44 byte range instead of 16-76 byte as your patch does. > > > > Since all important fields are supposed to be kept in 32 bytes anyway, > > they are still either at the start or the end of a given cache line, > > but never cross two. > > Another take would be to use a cacheline. But I guess the difference > between 32/64/cacheline is mostly academic, given the rate of changes > to struct dentry. There have been so many optimizations and misoptimizations regarding the dentry struct over the years. See http://lkml.org/lkml/2004/5/8/117 for the almost exact opposite of this patch, along with the same discussion that we're having now. Arnd <>< - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
