From ee947859bf8a357a45176b238dc9f9db11eb4d4e Mon Sep 17 00:00:00 2001 From: Mitko Haralanov Date: Mon, 26 Oct 2015 10:28:41 -0400 Subject: [PATCH] staging/rdma/hfi1: Allow tuning of SDMA interrupt rate The SDMA engines were configured to generate progress interrupts every time they processed N/2 descriptors (where N is the size of the descriptor queue). This interval was too infrequent, leading to degraded performance. This commit adds a module parameter, as well as a recommended default, which allows for the tuning of the interrupt frequency. Reviewed-by: Mike Marciniszyn Signed-off-by: Mitko Haralanov Signed-off-by: Ira Weiny Signed-off-by: Greg Kroah-Hartman --- drivers/staging/rdma/hfi1/sdma.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/staging/rdma/hfi1/sdma.c b/drivers/staging/rdma/hfi1/sdma.c index 0a39f3ee1449..64e63beacf1f 100644 --- a/drivers/staging/rdma/hfi1/sdma.c +++ b/drivers/staging/rdma/hfi1/sdma.c @@ -66,6 +66,7 @@ /* must be a power of 2 >= 64 <= 32768 */ #define SDMA_DESCQ_CNT 1024 +#define SDMA_DESC_INTR 64 #define INVALID_TAIL 0xffff static uint sdma_descq_cnt = SDMA_DESCQ_CNT; @@ -80,6 +81,10 @@ uint mod_num_sdma; module_param_named(num_sdma, mod_num_sdma, uint, S_IRUGO); MODULE_PARM_DESC(num_sdma, "Set max number SDMA engines to use"); +static uint sdma_desct_intr = SDMA_DESC_INTR; +module_param_named(desct_intr, sdma_desct_intr, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(desct_intr, "Number of SDMA descriptor before interrupt"); + #define SDMA_WAIT_BATCH_SIZE 20 /* max wait time for a SDMA engine to indicate it has halted */ #define SDMA_ERR_HALT_TIMEOUT 10 /* ms */ @@ -1046,6 +1051,9 @@ int sdma_init(struct hfi1_devdata *dd, u8 port) return -ENOMEM; idle_cnt = ns_to_cclock(dd, idle_cnt); + if (!sdma_desct_intr) + sdma_desct_intr = SDMA_DESC_INTR; + /* Allocate memory for SendDMA descriptor FIFOs */ for (this_idx = 0; this_idx < num_engines; ++this_idx) { sde = &dd->per_sdma[this_idx]; @@ -1546,7 +1554,7 @@ void sdma_engine_interrupt(struct sdma_engine *sde, u64 status) { trace_hfi1_sdma_engine_interrupt(sde, status); write_seqlock(&sde->head_lock); - sdma_set_desc_cnt(sde, sde->descq_cnt / 2); + sdma_set_desc_cnt(sde, sdma_desct_intr); sdma_make_progress(sde, status); write_sequnlock(&sde->head_lock); } -- 2.20.1