From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 09 Dec 2014 09:27:13 +0100 Subject: [RFC PATCH v2 1/4] arm64: defconfig: increase NR_CPUS range to 2-128 In-Reply-To: References: <1416605010-10442-1-git-send-email-ganapatrao.kulkarni@caviumnetworks.com> <3519779.ILzEnWe9lP@wuerfel> Message-ID: <2054688.iIEQnOEqVy@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Monday 08 December 2014 17:57:03 Zi Shen Lim wrote: > Hi Arnd, > > On Mon, Nov 24, 2014 at 3:53 AM, Arnd Bergmann wrote: > > > > On Saturday 22 November 2014 02:53:27 Ganapatrao Kulkarni wrote: > > > Raising the maximum limit to 128. This is needed for Cavium's > > > Thunder system that will have 96 cores on Multi-node system. > > > > > > Signed-off-by: Ganapatrao Kulkarni > > > > > > > Could we please raise the compile-time limit to the highest number that > > you are able to boot successfully on some existing machine? > > > > There isn't much point in doubling this every few months. > > Agreed. If we look back at [1], Mark Rutland has actually compiled and > boot-tested NR_CPUS=4096 on Juno. > > [1] https://lkml.org/lkml/2014/9/8/537 Ok, 4096 sounds like a good NR_CPUS limit then, it should last for a while. For the defconfig, we probably want a much smaller value, either one that covers all known machines (96 at this time), or something that covers 95% of all users (maybe 32?) and does not have an serious impact on memory consumption or performance on small machines. Arnd