On Fri, Sep 10, 2021 at 9:54 AM Bruce Richardson <bruce.richard...@intel.com> wrote: > > On Fri, Sep 10, 2021 at 08:51:04AM +0200, David Marchand wrote: > > On Thu, Sep 9, 2021 at 4:38 PM Bruce Richardson > > <bruce.richard...@intel.com> wrote: > > > > > > On Thu, Sep 09, 2021 at 02:45:06PM +0100, David Hunt wrote: > > > > Modern processors are coming with an ever increasing number of cores, > > > > and 128 does not seem like a sensible max limit any more, especially > > > > when you consider multi-socket systems with Hyper-Threading enabled. > > > > > > > > This patch increases max_lcores default from 128 to 512. > > > > > > > > Signed-off-by: David Hunt <david.h...@intel.com> > > > > Why should we need this? > > > > --lcores makes it possible to pin 128 lcores to any physical core on > > your system. > > And for applications that have their own thread management, they can > > pin thread, then use rte_thread_register. > > > > Do you have applications that require more than 128 lcores? > > > The trouble is that using the --lcores syntax for mapping high core numbers > to low lcore ids is much more awkward to use. Every case of DPDK use I've > seen uses -c with a coremask, or -l with just giving a few core numbers on > it. This simple scheme won't work with core numbers greater than 128, and > there are already systems available with more than that number of cores. > > Apart from the memory footprint issues - which this patch is already making > a good start in addressing, why would we not increase the default > max_lcores to that seen on real systems?
The memory footprint is a major issue to me, and reserving all those lcores won't be needed in any system. We will also have to decide on a "640k ought to be enough" value to avoid ABI issue with the next processor that comes out and has more than 512 cores. Could we wire the -c / -l options to --lcores behavior ? It breaks the 1:1 lcore/physical core assumption, but it solves your usability issue. -- David Marchand
