Scheduling out and in for every FW message can slow us down unnecessarily. Our experiments show that even under heavy load the FW responds to 99.9% messages within 200 us. Add a short busy wait before entering the wait queue.
Signed-off-by: Jakub Kicinski <[email protected]> --- drivers/net/ethernet/netronome/nfp/bpf/cmsg.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c b/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c index 71e6586acc36..80d3aa0fc9d3 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c +++ b/drivers/net/ethernet/netronome/nfp/bpf/cmsg.c @@ -157,7 +157,14 @@ nfp_bpf_cmsg_wait_reply(struct nfp_app_bpf *bpf, enum nfp_bpf_cmsg_type type, int tag) { struct sk_buff *skb; - int err; + int i, err; + + for (i = 0; i < 50; i++) { + udelay(4); + skb = nfp_bpf_reply(bpf, tag); + if (skb) + return skb; + } err = wait_event_interruptible_timeout(bpf->cmsg_wq, skb = nfp_bpf_reply(bpf, tag), -- 2.15.1
