summaryrefslogtreecommitdiffstats
path: root/include/rdma
diff options
context:
space:
mode:
authorMike Marciniszyn <mike.marciniszyn@intel.com>2016-02-14 12:45:36 -0800
committerDoug Ledford <dledford@redhat.com>2016-03-10 20:38:14 -0500
commit14553ca11039732bcba3c160a26d702dbe71dd49 (patch)
tree22415d51860e0fa1c0b11f4510d2550cb793e23c /include/rdma
parent4f8cc5c04f9445c4b1ef82769b5c0a0f1f8713c9 (diff)
downloadlinux-14553ca11039732bcba3c160a26d702dbe71dd49.tar.bz2
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/rdma')
-rw-r--r--include/rdma/rdmavt_qp.h22
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.