Lines Matching refs:queue

12 queue pairs in host memory. The term "host" is used a lot, so to clarify that's
13 the system that the NVMe SSD is plugged into. A queue pair consists of two
14 queues - a submission queue and a completion queue. These queues are more
16 queue is an array of 64 byte command structures, plus 2 integers (head and tail
17 indices). The completion queue is similarly an array of 16 byte completion
22 it into the submission queue at the current location of the submission queue
23 tail index, and then writing the new index of the submission queue tail to the
24 submission queue tail doorbell register. It's actually valid to copy a whole set
38 The completion queue works similarly, but the device is instead the one writing
40 and 1 on each loop through the entire ring. When a queue pair is set up to
41 generate interrupts, the interrupt contains the index of the completion queue
49 driver uses them. The user is going to construct a queue pair at some early time
54 NVMe queue pair to use. Finally, the user provides a callback function and
62 queue pair object - `struct spdk_nvme_qpair`. The number of requests allocated to
63 the queue pair is larger than the actual queue depth of the NVMe submission
64 queue because SPDK supports a couple of key convenience features. The first is
66 hardware queue can actually hold and SPDK will automatically queue in software.
68 which are outlined next. The number of request objects is configurable at queue
70 on the hardware queue depth.
74 submission queue slot. Once the command has been constructed, SPDK attempts to
75 obtain an open slot in the NVMe submission queue. For each element in the
76 submission queue an object called a tracker is allocated. The trackers are
109 submission queue slot and then rings the submission queue tail doorbell to tell
114 SPDK to examine the completion queue. Specifically, it reads the phase bit of
122 write the completion queue head doorbell to let the device know that it can use
123 the completion queue slots for new completions and return.