mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-27 02:17:36 -04:00
dd1ed10817
When there are many RC QPs and an RDMA READ request is sent, timeouts occur on the requester side because of fairness among RC QPs on their relative SDMA engine on the responder side. This also hits write and send, but to a lesser extent. Complicating the issue is that the current code checks if workqueue is congested before scheduling other QPs, however, this check is based on the number of active entries in the workqueue, which was found to be too big to for workqueue_congested() to be effective. Fix by reducing the number of active entries as revealed by experimentation from the default of num_sdma to HFI1_MAX_ACTIVE_WORKQUEUE_ENTRIES. Retry counts were monitored to determine the correct value. Tracing to investigate any future issues is also added. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.