IB/hfi1: Add packet histogram trace event

Add a simple trace event taking context number and building simple
histogram to print packets distribution between contexts.

Link: https://lore.kernel.org/r/20200511160700.173205.84270.stgit@awfm-01.aw.intel.comReviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hfi1/driver.c

@@ -1706,6 +1706,7 @@ static void hfi1_ipoib_ib_rcv(struct hfi1_packet *packet)
 		goto drop_no_nd;
 
 	trace_input_ibhdr(rcd->dd, packet, !!(rhf_dc_info(packet->rhf)));
+	trace_ctxt_rsm_hist(rcd->ctxt);
 
 	/* handle congestion notifications */
 	do_work = hfi1_may_ecn(packet);

drivers/infiniband/hw/hfi1/trace.c

@@ -520,6 +520,38 @@ u16 hfi1_trace_get_tid_idx(u32 ent)
 	return EXP_TID_GET(ent, IDX);
 }
 
+struct hfi1_ctxt_hist {
+	atomic_t count;
+	atomic_t data[255];
+};
+
+struct hfi1_ctxt_hist hist = {
+	.count = ATOMIC_INIT(0)
+};
+
+const char *hfi1_trace_print_rsm_hist(struct trace_seq *p, unsigned int ctxt)
+{
+	int i, len = ARRAY_SIZE(hist.data);
+	const char *ret = trace_seq_buffer_ptr(p);
+	unsigned long packet_count = atomic_fetch_inc(&hist.count);
+
+	trace_seq_printf(p, "packet[%lu]", packet_count);
+	for (i = 0; i < len; ++i) {
+		unsigned long val;
+		atomic_t *count = &hist.data[i];
+
+		if (ctxt == i)
+			val = atomic_fetch_inc(count);
+		else
+			val = atomic_read(count);
+
+		if (val)
+			trace_seq_printf(p, "(%d:%lu)", i, val);
+	}
+	trace_seq_putc(p, 0);
+	return ret;
+}
+
 __hfi1_trace_fn(AFFINITY);
 __hfi1_trace_fn(PKT);
 __hfi1_trace_fn(PROC);

drivers/infiniband/hw/hfi1/trace_ctxts.h

 /*
-* Copyright(c) 2015, 2016 Intel Corporation.
+* Copyright(c) 2015 - 2020 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
@@ -138,6 +138,15 @@ TRACE_EVENT(hfi1_ctxt_info,
 		      )
 );
 
+const char *hfi1_trace_print_rsm_hist(struct trace_seq *p, unsigned int ctxt);
+TRACE_EVENT(ctxt_rsm_hist,
+	    TP_PROTO(unsigned int ctxt),
+	    TP_ARGS(ctxt),
+	    TP_STRUCT__entry(__field(unsigned int, ctxt)),
+	    TP_fast_assign(__entry->ctxt = ctxt;),
+	    TP_printk("%s", hfi1_trace_print_rsm_hist(p, __entry->ctxt))
+);
+
 #endif /* __HFI1_TRACE_CTXTS_H */
 
 #undef TRACE_INCLUDE_PATH