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Dario Faggioli
bcb3914e1f
In fact, credit2 uses CPU topology to decide how to arrange its internal runqueues. Before this change, only 'one runqueue per socket' was allowed. However, experiments have shown that, for instance, having one runqueue per physical core improves performance, especially in case hyperthreading is available. In general, it makes sense to allow users to pick one runqueue arrangement at boot time, so that: - more experiments can be easily performed to even better assess and improve performance; - one can select the best configuration for his specific use case and/or hardware. This patch enables the above. Note that, for correctly arranging runqueues to be per-core, just checking cpu_to_core() on the host CPUs is not enough. In fact, cores (and hyperthreads) on different sockets, can have the same core (and thread) IDs! We, therefore, need to check whether the full topology of two CPUs matches, for them to be put in the same runqueue. Note also that the default (although not functional) for credit2, since now, has been per-socket runqueue. This patch leaves things that way, to avoid mixing policy and technical changes. Finally, it would be a nice feature to be able to select a particular runqueue arrangement, even when creating a Credit2 cpupool. This is left as future work. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Signed-off-by: Uma Sharma <uma.sharma523@gmail.com> Reviewed-by: Juergen Gross <jgross@suse.com> Reviewed-by: George Dunlap <george.dunlap@citrix.com>
xen-bugtool =========== The xen-bugtool command line application will collate the Xen dmesg output, details of the hardware configuration of your machine, information about the build of Xen that you are using, plus, if you allow it, various logs. The information collated can either be posted to a Xen Bugzilla bug (this bug must already exist in the system, and you must be a registered user there), or it can be saved as a .tar.bz2 for sending or archiving. The collated logs may contain private information, and if you are at all worried about that, you should not use this tool, or you should explicitly exclude those logs from the archive. xen-bugtool is wholly interactive, so simply run it, and answer the questions.