From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <200009202041.QAA25046@mal-ach.watson.ibm.com> To: Dan Malek cc: Roman Zippel , paulus@linuxcare.com.au, Geert Uytterhoeven , Linux/PPC Development Subject: Re: __ioremap_at() in 2.4.0-test9-pre2 In-Reply-To: Message from Dan Malek of "Wed, 20 Sep 2000 14:11:40 EDT." <39C8FDDC.29AEDE52@mvista.com> Date: Wed, 20 Sep 2000 16:41:03 -0400 From: David Edelsohn Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: >>>>> Dan Malek writes: Dan> None of the embedded PowerPCs use a hash table, and the Book E Dan> processors don't either. We avoid using the hash table when given Dan> the option, like 603s. The "hardware assist" and subsequent hash Dan> table is a PITA for Linux VM, and Cort has documented the performance Dan> benefits of not using it. Avoiding the hash table on PowerPC only is an advantage because the PowerPC Linux kernel implements some "optimizations" which do not match the PowerPC architecture very well. Avoiding the hash tables recovers some of the performance lost because of the earlier work, so it is a relative benefit but not an absolute benefit over a better kernel design. David ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/