On 28 Feb 2019, at 19:50, Dumitrescu, Cristian wrote:
Hi Eelco,
Sorry for my delayed reply
No problem I was OOO also so hence my late reply ;)
-----Original Message-----
From: Eelco Chaudron [mailto:echau...@redhat.com]
Sent: Friday, February 1, 2019 4:07 PM
To: Dumitrescu, Cristian <cristian.dumitre...@intel.com>
Cc: dev@dpdk.org
Subject: [PATCH v2] lib/librte_meter: fix divide by zero for RFC4115
meter
RFC 4115 allows a meter with either cir and/or eir configured.
When only one is configured a divide by zero would occur.
Fixes: 655796d2b5fb ("meter: support RFC4115 trTCM")
Cc: echau...@redhat.com
Signed-off-by: Eelco Chaudron <echau...@redhat.com>
---
v2 - Removed configuration change that got included by accident
lib/librte_meter/rte_meter.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/lib/librte_meter/rte_meter.h
b/lib/librte_meter/rte_meter.h
index 005e4eeee..56d85ecf0 100644
--- a/lib/librte_meter/rte_meter.h
+++ b/lib/librte_meter/rte_meter.h
@@ -597,8 +597,8 @@ rte_meter_trtcm_rfc4115_color_blind_check(
/* Bucket update */
time_diff_tc = time - m->time_tc;
time_diff_te = time - m->time_te;
- n_periods_tc = time_diff_tc / p->cir_period;
- n_periods_te = time_diff_te / p->eir_period;
+ n_periods_tc = p->cir_period != 0 ? time_diff_tc / p->cir_period :
0;
+ n_periods_te = p->eir_period != 0 ? time_diff_te / p->eir_period :
0;
m->time_tc += n_periods_tc * p->cir_period;
m->time_te += n_periods_te * p->eir_period;
@@ -641,8 +641,8 @@ rte_meter_trtcm_rfc4115_color_aware_check(
/* Bucket update */
time_diff_tc = time - m->time_tc;
time_diff_te = time - m->time_te;
- n_periods_tc = time_diff_tc / p->cir_period;
- n_periods_te = time_diff_te / p->eir_period;
+ n_periods_tc = p->cir_period != 0 ? time_diff_tc / p->cir_period :
0;
+ n_periods_te = p->eir_period != 0 ? time_diff_te / p->eir_period :
0;
m->time_tc += n_periods_tc * p->cir_period;
m->time_te += n_periods_te * p->eir_period;
Yes, this is indeed an issue, good catch!
For performance reasons, we'd like to avoid a test on the fast path
(rte_meter_xyz_check) and replace it with more work done on the
configuration stage (rte_meter_profile_xyz_config), if possible.
We can intercept the null CIR or EIR cases very early in
rte_meter_trtcm_rfc4115_profile_config() and deal with them separately
by setting the CIR/EIR period and bytes_per_period to some neutral
values and skipping the call to rte_meter_get_tb_params(): period =
RTE_METER_TB_PERIOD_MIN, bytes_per_period = 0.
Excellent idea, will sent out a v3 soon, after some testing…
//Eelco
