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author | Mike Marciniszyn <mike.marciniszyn@intel.com> | 2016-02-14 23:45:36 +0300 |
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committer | Doug Ledford <dledford@redhat.com> | 2016-03-11 04:38:14 +0300 |
commit | 14553ca11039732bcba3c160a26d702dbe71dd49 (patch) | |
tree | 22415d51860e0fa1c0b11f4510d2550cb793e23c /include | |
parent | 4f8cc5c04f9445c4b1ef82769b5c0a0f1f8713c9 (diff) | |
download | linux-14553ca11039732bcba3c160a26d702dbe71dd49.tar.xz |
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 'include')
-rw-r--r-- | include/rdma/rdmavt_qp.h | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h index 5c307ed4d195..f2f4df023aaa 100644 --- a/include/rdma/rdmavt_qp.h +++ b/include/rdma/rdmavt_qp.h @@ -82,6 +82,7 @@ * RVT_S_WAIT_DMA - waiting for send DMA queue to drain before generating * next send completion entry not via send DMA * RVT_S_WAIT_PIO - waiting for a send buffer to be available + * RVT_S_WAIT_PIO_DRAIN - waiting for a qp to drain pio packets * RVT_S_WAIT_TX - waiting for a struct verbs_txreq to be available * RVT_S_WAIT_DMA_DESC - waiting for DMA descriptors to be available * RVT_S_WAIT_KMEM - waiting for kernel memory to be available @@ -101,16 +102,17 @@ #define RVT_S_WAIT_SSN_CREDIT 0x0100 #define RVT_S_WAIT_DMA 0x0200 #define RVT_S_WAIT_PIO 0x0400 -#define RVT_S_WAIT_TX 0x0800 -#define RVT_S_WAIT_DMA_DESC 0x1000 -#define RVT_S_WAIT_KMEM 0x2000 -#define RVT_S_WAIT_PSN 0x4000 -#define RVT_S_WAIT_ACK 0x8000 -#define RVT_S_SEND_ONE 0x10000 -#define RVT_S_UNLIMITED_CREDIT 0x20000 -#define RVT_S_AHG_VALID 0x40000 -#define RVT_S_AHG_CLEAR 0x80000 -#define RVT_S_ECN 0x100000 +#define RVT_S_WAIT_PIO_DRAIN 0x0800 +#define RVT_S_WAIT_TX 0x1000 +#define RVT_S_WAIT_DMA_DESC 0x2000 +#define RVT_S_WAIT_KMEM 0x4000 +#define RVT_S_WAIT_PSN 0x8000 +#define RVT_S_WAIT_ACK 0x10000 +#define RVT_S_SEND_ONE 0x20000 +#define RVT_S_UNLIMITED_CREDIT 0x40000 +#define RVT_S_AHG_VALID 0x80000 +#define RVT_S_AHG_CLEAR 0x100000 +#define RVT_S_ECN 0x200000 /* * Wait flags that would prevent any packet type from being sent. |