Re: [PATCH] app/test-fib: fix possible division by zero

[Medvedkin, Vladimir]

Hi Kevin,

On 11/01/2022 17:15, Kevin Traynor wrote:
On 23/12/2021 15:25, Vladimir Medvedkin wrote:
This patch fixes the division by 0, which occurs if the number of 
routes is less than 10.
Can be triggered by passing -n argument with value < 10:

9 causing a divide by zero - another example of inflation :-)


Too bad that we are not working in a wheel 
(https://en.wikipedia.org/wiki/Wheel_theory), where division by 0 is 
always defined :)

./dpdk-test-fib -- -n 9
...
Floating point exception (core dumped)

Fixes: 103809d032cd ("app/test-fib: add test application for FIB")
Cc: vladimir.medved...@intel.com


You probably want to add 'Cc: sta...@dpdk.org' for this.

Signed-off-by: Vladimir Medvedkin <vladimir.medved...@intel.com>
---
  app/test-fib/main.c | 40 ++++++++++++++++++++++++----------------
  1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/app/test-fib/main.c b/app/test-fib/main.c
index ecd420116a..9bc8b8a7ca 100644
--- a/app/test-fib/main.c
+++ b/app/test-fib/main.c
@@ -902,8 +902,9 @@ run_v4(void)
                  return -ret;
              }
          }
-        printf("AVG FIB add %"PRIu64"\n",
-            (rte_rdtsc_precise() - start) / j);
+        if (j != 0)
+            printf("AVG FIB add %"PRIu64"\n",
+                (rte_rdtsc_precise() - start) / j);


You are just not printing the result for these cases. Do you think it is 
worth to print a warning message (one), and update any documentation so 
the user is aware of the acceptable bounds?


Agree, I'll send v2

          i += j;
      }
@@ -930,8 +931,9 @@ run_v4(void)
                      return -ret;
                  }
              }
-            printf("AVG LPM add %"PRIu64"\n",
-                (rte_rdtsc_precise() - start) / j);
+            if (j != 0)
+                printf("AVG LPM add %"PRIu64"\n",
+                    (rte_rdtsc_precise() - start) / j);
              i += j;
          }
      }
@@ -984,8 +986,9 @@ run_v4(void)
          for (j = 0; j < (config.nb_routes - i) / k; j++)
              rte_fib_delete(fib, rt[i + j].addr, rt[i + j].depth);
-        printf("AVG FIB delete %"PRIu64"\n",
-            (rte_rdtsc_precise() - start) / j);
+        if (j != 0)
+            printf("AVG FIB delete %"PRIu64"\n",
+                (rte_rdtsc_precise() - start) / j);
          i += j;
      }
@@ -996,8 +999,9 @@ run_v4(void)
                  rte_lpm_delete(lpm, rt[i + j].addr,
                      rt[i + j].depth);
-            printf("AVG LPM delete %"PRIu64"\n",
-                (rte_rdtsc_precise() - start) / j);
+            if (j != 0)
+                printf("AVG LPM delete %"PRIu64"\n",
+                    (rte_rdtsc_precise() - start) / j);
              i += j;
          }
      }
@@ -1097,8 +1101,9 @@ run_v6(void)
                  return -ret;
              }
          }
-        printf("AVG FIB add %"PRIu64"\n",
-            (rte_rdtsc_precise() - start) / j);
+        if (j != 0)
+            printf("AVG FIB add %"PRIu64"\n",
+                (rte_rdtsc_precise() - start) / j);
          i += j;
      }
@@ -1125,8 +1130,9 @@ run_v6(void)
                      return -ret;
                  }
              }
-            printf("AVG LPM add %"PRIu64"\n",
-                (rte_rdtsc_precise() - start) / j);
+            if (j != 0)
+                printf("AVG LPM add %"PRIu64"\n",
+                    (rte_rdtsc_precise() - start) / j);
              i += j;
          }
      }
@@ -1183,8 +1189,9 @@ run_v6(void)
          for (j = 0; j < (config.nb_routes - i) / k; j++)
              rte_fib6_delete(fib, rt[i + j].addr, rt[i + j].depth);
-        printf("AVG FIB delete %"PRIu64"\n",
-            (rte_rdtsc_precise() - start) / j);
+        if (j != 0)
+            printf("AVG FIB delete %"PRIu64"\n",
+                (rte_rdtsc_precise() - start) / j);
          i += j;
      }
@@ -1195,8 +1202,9 @@ run_v6(void)
                  rte_lpm6_delete(lpm, rt[i + j].addr,
                      rt[i + j].depth);
-            printf("AVG LPM delete %"PRIu64"\n",
-                (rte_rdtsc_precise() - start) / j);
+            if (j != 0)
+                printf("AVG LPM delete %"PRIu64"\n",
+                    (rte_rdtsc_precise() - start) / j);
              i += j;
          }
      }



--
Regards,
Vladimir