diff mbox

[dpdk-dev,v2] meter: fix excess token bucket update in srtcm implementation

Message ID 1474437462-6955-1-git-send-email-nikhil.jagtap@gmail.com (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers

Commit Message

Nikhil Jagtap Sept. 21, 2016, 5:57 a.m. UTC 
  As per srTCM RFC 2697, we should be updating the E bucket only after the
C bucket overflows. This patch fixes the current DPDK implementation,
where we are updating both the buckets simultaneously at the same rate
(CIR) which results in token accumulation rate of (2*CIR).

Signed-off-by: Nikhil Jagtap <nikhil.jagtap@gmail.com>
---

v2:
Removed the else part and instead added a default initialization of te.

---
 lib/librte_meter/rte_meter.h |   24 ++++++++++++++----------
 1 files changed, 14 insertions(+), 10 deletions(-)

Comments

Cristian Dumitrescu Sept. 21, 2016, 8:57 a.m. UTC | #1 
> -----Original Message-----
> From: Nikhil Jagtap [mailto:nikhil.jagtap@gmail.com]
> Sent: Wednesday, September 21, 2016 6:58 AM
> To: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
> Cc: dev@dpdk.org; Ramia, Kannan Babu <kannan.babu.ramia@intel.com>;
> Nikhil Jagtap <nikhil.jagtap@gmail.com>
> Subject: [PATCH v2] meter: fix excess token bucket update in srtcm
> implementation
> 
> As per srTCM RFC 2697, we should be updating the E bucket only after the
> C bucket overflows. This patch fixes the current DPDK implementation,
> where we are updating both the buckets simultaneously at the same rate
> (CIR) which results in token accumulation rate of (2*CIR).
> 
> Signed-off-by: Nikhil Jagtap <nikhil.jagtap@gmail.com>
> ---
> 
> v2:
> Removed the else part and instead added a default initialization of te.
> 
> ---
>  lib/librte_meter/rte_meter.h |   24 ++++++++++++++----------
>  1 files changed, 14 insertions(+), 10 deletions(-)
> 

Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

Thanks, Nikhil!
Thomas Monjalon Sept. 21, 2016, 9:19 p.m. UTC | #2 
> > As per srTCM RFC 2697, we should be updating the E bucket only after the
> > C bucket overflows. This patch fixes the current DPDK implementation,
> > where we are updating both the buckets simultaneously at the same rate
> > (CIR) which results in token accumulation rate of (2*CIR).
> > 
> > Signed-off-by: Nikhil Jagtap <nikhil.jagtap@gmail.com>
> 
> Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

Applied, thanks
diff mbox

Patch

diff --git a/lib/librte_meter/rte_meter.h b/lib/librte_meter/rte_meter.h
index 2cd8d81..2ab7184 100644
--- a/lib/librte_meter/rte_meter.h
+++ b/lib/librte_meter/rte_meter.h
@@ -232,13 +232,15 @@  rte_meter_srtcm_color_blind_check(struct rte_meter_srtcm *m,
 	n_periods = time_diff / m->cir_period;
 	m->time += n_periods * m->cir_period;
 
+	/* Put the tokens overflowing from tc into te bucket */
 	tc = m->tc + n_periods * m->cir_bytes_per_period;
-	if (tc > m->cbs)
+	te = m->te;
+	if (tc > m->cbs) {
+		te += (tc - m->cbs);
+		if (te > m->ebs)
+			te = m->ebs;
 		tc = m->cbs;
-
-	te = m->te + n_periods * m->cir_bytes_per_period;
-	if (te > m->ebs)
-		te = m->ebs;
+	}
 
 	/* Color logic */
 	if (tc >= pkt_len) {
@@ -271,13 +273,15 @@  rte_meter_srtcm_color_aware_check(struct rte_meter_srtcm *m,
 	n_periods = time_diff / m->cir_period;
 	m->time += n_periods * m->cir_period;
 
+	/* Put the tokens overflowing from tc into te bucket */
 	tc = m->tc + n_periods * m->cir_bytes_per_period;
-	if (tc > m->cbs)
+	te = m->te;
+	if (tc > m->cbs) {
+		te += (tc - m->cbs);
+		if (te > m->ebs)
+			te = m->ebs;
 		tc = m->cbs;
-
-	te = m->te + n_periods * m->cir_bytes_per_period;
-	if (te > m->ebs)
-		te = m->ebs;
+	}
 
 	/* Color logic */
 	if ((pkt_color == e_RTE_METER_GREEN) && (tc >= pkt_len)) {