diff options
author | Mike Marciniszyn | 2016-02-14 21:45:36 +0100 |
---|---|---|
committer | Doug Ledford | 2016-03-11 02:38:14 +0100 |
commit | 14553ca11039732bcba3c160a26d702dbe71dd49 (patch) | |
tree | 22415d51860e0fa1c0b11f4510d2550cb793e23c /drivers/staging/rdma/hfi1/chip.h | |
parent | staging/rdma/hfi1: use u8 for vl/sl (diff) | |
download | kernel-qcow2-linux-14553ca11039732bcba3c160a26d702dbe71dd49.tar.gz kernel-qcow2-linux-14553ca11039732bcba3c160a26d702dbe71dd49.tar.xz kernel-qcow2-linux-14553ca11039732bcba3c160a26d702dbe71dd49.zip |
staging/rdma/hfi1: Adaptive PIO for short messages
The change requires a new pio_busy field in the iowait structure to
track the number of outstanding pios. The new counter together
with the sdma counter serve as the basis for a packet by packet decision
as to which egress mechanism to use. Since packets given to different
egress mechanisms are not ordered, this scheme will preserve the order.
The iowait drain/wait mechanisms are extended for a pio case. An
additional qp wait flag is added for the PIO drain wait case.
Currently the only pio wait is for buffers, so the no_bufs_available()
routine name is changed to pio_wait() and a third argument is passed
with one of the two pio wait flags to generalize the routine. A module
parameter is added to hold a configurable threshold. For now, the
module parameter is zero.
A heuristic routine is added to return the func pointer of the proper
egress routine to use.
The heuristic is as follows:
- SMI always uses pio
- GSI,UD qps <= threshold use pio
- UD qps > threadhold use sdma
o No coordination with sdma is required because order is not required
and this qp pio count is not maintained for UD
- RC/UC ONLY packets <= threshold chose as follows:
o If sdmas pending, use SDMA
o Otherwise use pio and enable the pio tracking count at
the time the pio buffer is allocated
- RC/UC ONLY packets > threshold use SDMA
o If pio's are pending the pio_wait with the new wait flag is
called to delay for pios to drain
The threshold is potentially reduced by the QP's mtu.
The sc_buffer_alloc() has two additional args (a callback, a void *)
which are exploited by the RC/UC cases to pass a new complete routine
and a qp *.
When the shadow ring completes the credit associated with a packet,
the new complete routine is called. The verbs_pio_complete() will then
decrement the busy count and trigger any drain waiters in qp destroy
or reset.
Reviewed-by: Jubin John <jubin.john@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/staging/rdma/hfi1/chip.h')
-rw-r--r-- | drivers/staging/rdma/hfi1/chip.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/staging/rdma/hfi1/chip.h b/drivers/staging/rdma/hfi1/chip.h index b86c220161e5..6c581e0bd65f 100644 --- a/drivers/staging/rdma/hfi1/chip.h +++ b/drivers/staging/rdma/hfi1/chip.h @@ -800,6 +800,7 @@ enum { C_SW_CPU_RCV_LIM, C_SW_VTX_WAIT, C_SW_PIO_WAIT, + C_SW_PIO_DRAIN, C_SW_KMEM_WAIT, C_SW_SEND_SCHED, C_SDMA_DESC_FETCHED_CNT, |