[dpdk-dev] [PATCH v2] eal: add additional info if lcore exceeds max cores

[David Hunt <david.hunt@intel.com>]

If the user requests to use an lcore above 128 using -l or -c,
the eal will exit with "EAL: invalid core list syntax" and
very little other useful information.

This patch adds some extra information suggesting to use --lcores
so that physical cores above RTE_MAX_LCORE (default 128) can be
used. This is achieved by using the --lcores option by mapping
the logical cores in the application onto to physical cores.

There is no change in functionalty, just additional messages
suggesting how the --lcores option might be used for the supplied
list of lcores. For example, if "-l 12-14,130,132" is used, we
see the following additional output on the command line:

EAL: Error = One of the 5 cores provided exceeds RTE_MAX_LCORE (128)
EAL: Please use --lcores instead, e.g. --lcores 0@12,1@13,2@14,3@130,4@132

Signed-off-by: David Hunt <david.hunt@intel.com>

---
changes in v2
   * Rather than increasing the default max lcores (as in v1),
     it was agreed to do this instead (switch to --lcores).
   * As the other patches in the v1 of the set are no longer related
     to this change, I'll submit as a separate patch set.
---
 lib/eal/common/eal_common_options.c | 31 +++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/lib/eal/common/eal_common_options.c b/lib/eal/common/eal_common_options.c
index ff5861b5f3..5c7a5a45a5 100644
--- a/lib/eal/common/eal_common_options.c
+++ b/lib/eal/common/eal_common_options.c
@@ -836,6 +836,8 @@ eal_parse_service_corelist(const char *corelist)
 	return 0;
 }
 
+#define MAX_LCORES_STRING 512
+
 static int
 eal_parse_corelist(const char *corelist, int *cores)
 {
@@ -843,6 +845,9 @@ eal_parse_corelist(const char *corelist, int *cores)
 	char *end = NULL;
 	int min, max;
 	int idx;
+	bool overflow = false;
+	char lcores[MAX_LCORES_STRING] = "";
+	int len = 0;
 
 	for (idx = 0; idx < RTE_MAX_LCORE; idx++)
 		cores[idx] = -1;
@@ -862,8 +867,10 @@ eal_parse_corelist(const char *corelist, int *cores)
 		idx = strtol(corelist, &end, 10);
 		if (errno || end == NULL)
 			return -1;
-		if (idx < 0 || idx >= RTE_MAX_LCORE)
+		if (idx < 0)
 			return -1;
+		if (idx >= RTE_MAX_LCORE)
+			overflow = true;
 		while (isblank(*end))
 			end++;
 		if (*end == '-') {
@@ -873,10 +880,19 @@ eal_parse_corelist(const char *corelist, int *cores)
 			if (min == RTE_MAX_LCORE)
 				min = idx;
 			for (idx = min; idx <= max; idx++) {
-				if (cores[idx] == -1) {
-					cores[idx] = count;
-					count++;
+				if (idx < RTE_MAX_LCORE) {
+					if (cores[idx] == -1)
+						cores[idx] = count;
 				}
+				count++;
+				if (count == 1)
+					len = len + snprintf(&lcores[len],
+							MAX_LCORES_STRING - len,
+							"%d@%d", count-1, idx);
+				else
+					len = len + snprintf(&lcores[len],
+							MAX_LCORES_STRING - len,
+							",%d@%d", count-1, idx);
 			}
 			min = RTE_MAX_LCORE;
 		} else
@@ -886,6 +902,13 @@ eal_parse_corelist(const char *corelist, int *cores)
 
 	if (count == 0)
 		return -1;
+	if (overflow) {
+		RTE_LOG(ERR, EAL, "Error = One of the %d cores provided exceeds RTE_MAX_LCORE (%d)\n",
+				count, RTE_MAX_LCORE);
+		RTE_LOG(ERR, EAL, "Please use --lcores instead, e.g. --lcores %s\n",
+				lcores);
+		return -1;
+	}
 	return 0;
 }
 
-- 
2.17.1