[PATCH iproute2 0/2] tc: pie: make tc/q_pie.c consistent with the kernel

[PATCH iproute2 0/2] tc: pie: make tc/q_pie.c consistent with the kernel

[Leslie Monis]

The PIE qdisc implementation in Linux has recently been
aligned with RFC 8033. This patch series makes tc/q_pie.c
consistent with that implementation and also updates the man
page tc-pie(8).

Leslie Monis (2):
  tc: pie: change maximum integer value of tc_pie_xstats->prob
  tc: pie: update man page

 man/man8/tc-pie.8 | 40 ++++++++++++++++++----------------------
 man/man8/tc.8     |  1 +
 tc/q_pie.c        |  2 +-
 3 files changed, 20 insertions(+), 23 deletions(-)

-- 
2.17.1

[PATCH iproute2 1/2] tc: pie: change maximum integer value of tc_pie_xstats->prob

[Leslie Monis]

tc_pie_xstats->prob has a maximum value of (2^64 - 1).

Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
---
 tc/q_pie.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tc/q_pie.c b/tc/q_pie.c
index f7924ef5..6566ca10 100644
--- a/tc/q_pie.c
+++ b/tc/q_pie.c
@@ -198,7 +198,7 @@ static int pie_print_xstats(struct qdisc_util *qu, FILE *f,
 	st = RTA_DATA(xstats);
 	/*prob is returned as a fracion of maximum integer value */
 	fprintf(f, "prob %f delay %uus avg_dq_rate %u\n",
-		(double)st->prob / (double)0xffffffff, st->delay,
+		(double)st->prob / (double)0xffffffffffffffff, st->delay,
 		st->avg_dq_rate);
 	fprintf(f, "pkts_in %u overlimit %u dropped %u maxq %u ecn_mark %u\n",
 		st->packets_in, st->overlimit, st->dropped, st->maxq,
-- 
2.17.1

Re: [PATCH iproute2 1/2] tc: pie: change maximum integer value of tc_pie_xstats->prob

[Stephen Hemminger]

On Sun, 24 Mar 2019 00:18:34 +0530
Leslie Monis <lesliemonis@gmail.com> wrote:

> tc_pie_xstats->prob has a maximum value of (2^64 - 1).
> 
> Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
> ---
>  tc/q_pie.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tc/q_pie.c b/tc/q_pie.c
> index f7924ef5..6566ca10 100644
> --- a/tc/q_pie.c
> +++ b/tc/q_pie.c
> @@ -198,7 +198,7 @@ static int pie_print_xstats(struct qdisc_util *qu, FILE *f,
>  	st = RTA_DATA(xstats);
>  	/*prob is returned as a fracion of maximum integer value */
>  	fprintf(f, "prob %f delay %uus avg_dq_rate %u\n",
> -		(double)st->prob / (double)0xffffffff, st->delay,
> +		(double)st->prob / (double)0xffffffffffffffff, st->delay,

This won't work correctly on 32bit systems because that value won't fit there.. You would be better off using UINT64_MAX

Re: [PATCH iproute2 1/2] tc: pie: change maximum integer value of tc_pie_xstats->prob

[Leslie Monis]

On Wed, Mar 27, 2019 at 07:53:57AM -0700, Stephen Hemminger wrote:
> On Sun, 24 Mar 2019 00:18:34 +0530
> Leslie Monis <lesliemonis@gmail.com> wrote:
> 
> > tc_pie_xstats->prob has a maximum value of (2^64 - 1).
> > 
> > Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
> > ---
> >  tc/q_pie.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tc/q_pie.c b/tc/q_pie.c
> > index f7924ef5..6566ca10 100644
> > --- a/tc/q_pie.c
> > +++ b/tc/q_pie.c
> > @@ -198,7 +198,7 @@ static int pie_print_xstats(struct qdisc_util *qu, FILE *f,
> >  	st = RTA_DATA(xstats);
> >  	/*prob is returned as a fracion of maximum integer value */
> >  	fprintf(f, "prob %f delay %uus avg_dq_rate %u\n",
> > -		(double)st->prob / (double)0xffffffff, st->delay,
> > +		(double)st->prob / (double)0xffffffffffffffff, st->delay,
> 
> This won't work correctly on 32bit systems because that value won't fit there.. You would be better off using UINT64_MAX

Alright. I will correct this.
Thanks

[PATCH iproute2 2/2] tc: pie: update man page

[Leslie Monis]

Update man page to reflect the changes made in Linux.

Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
---
 man/man8/tc-pie.8 | 40 ++++++++++++++++++----------------------
 man/man8/tc.8     |  1 +
 2 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/man/man8/tc-pie.8 b/man/man8/tc-pie.8
index 278293bd..a302132f 100644
--- a/man/man8/tc-pie.8
+++ b/man/man8/tc-pie.8
@@ -60,10 +60,10 @@ limit on the queue size in packets. Incoming packets are dropped when this limit
 is reached. Default is 1000 packets.
 
 .SS target
-is the expected queue delay. The default target delay is 20ms.
+is the expected queue delay. The default target delay is 15ms.
 
 .SS tupdate
-is the frequency at which the system drop probability is calculated. The default is 30ms.
+is the frequency at which the system drop probability is calculated. The default is 15ms.
 
 .SS alpha
 .SS beta
@@ -91,29 +91,27 @@ is turned off.
 .SH EXAMPLES
  # tc qdisc add dev eth0 root pie
  # tc -s qdisc show
-   qdisc pie 8034: dev eth0 root refcnt 2 limit 200p target 19000us tupdate 29000us alpha 2 beta 20
-   Sent 7443524 bytes 7204 pkt (dropped 900, overlimits 0 requeues 0)
-   backlog 38998b 37p requeues 0
-   prob 0.123384 delay 25000us avg_dq_rate 1464840
-   pkts_in 7241 overlimit 900 dropped 0 maxq 186 ecn_mark 0
+   qdisc pie 8036: dev eth0 root refcnt 2 limit 1000p target 15.0ms tupdate 16.0ms alpha 2 beta 20
+    Sent 31216108 bytes 20800 pkt (dropped 80, overlimits 0 requeues 0)
+    backlog 16654b 11p requeues 0
+   prob 0.006161 delay 15666us avg_dq_rate 1159667
+   pkts_in 20811 overlimit 0 dropped 80 maxq 50 ecn_mark 0
 
  # tc qdisc add dev eth0 root pie limit 100 target 20ms tupdate 30ms ecn
  # tc -s qdisc show
-   qdisc pie 8036: dev eth0 root refcnt 2 limit 200p target 19000 tupdate 29000 alpha 2 beta 20 ecn
-   Sent 2491922 bytes 2507 pkt (dropped 214, overlimits 0 requeues 0)
-   backlog 33728b 32p requeues 0
-   prob 0.102262 delay 24000us avg_dq_rate 1464840
-   pkts_in 2468 overlimit 214 dropped 0 maxq 192 ecn_mark 71
-
+   qdisc pie 8036: dev eth0 root refcnt 2 limit 100p target 20.0ms tupdate 32.0ms alpha 2 beta 20 ecn
+    Sent 6591724 bytes 4442 pkt (dropped 27, overlimits 0 requeues 0)
+    backlog 18168b 12p requeues 0
+   prob 0.008845 delay 11348us avg_dq_rate 1342773
+   pkts_in 4454 overlimit 0 dropped 27 maxq 65 ecn_mark 0
 
  # tc qdisc add dev eth0 root pie limit 100 target 50ms tupdate 30ms bytemode
  # tc -s qdisc show
-   qdisc pie 8036: dev eth0 root refcnt 2 limit 200p target 19000 tupdate 29000 alpha 2 beta 20 ecn
-   Sent 2491922 bytes 2507 pkt (dropped 214, overlimits 0 requeues 0)
-   backlog 33728b 32p requeues 0
-   prob 0.102262 delay 24000us avg_dq_rate 1464840
-   pkts_in 2468 overlimit 214 dropped 0 maxq 192 ecn_mark 71
-
+   qdisc pie 8036: dev eth0 root refcnt 2 limit 100p target 50.0ms tupdate 32.0ms alpha 2 beta 20 bytemode
+    Sent 1616274 bytes 1137 pkt (dropped 0, overlimits 0 requeues 0)
+    backlog 13626b 9p requeues 0
+   prob 0.000000 delay 0us avg_dq_rate 0
+   pkts_in 1146 overlimit 0 dropped 0 maxq 23 ecn_mark 0
 
 .SH SEE ALSO
 .BR tc (8),
@@ -121,9 +119,7 @@ is turned off.
 .BR tc-red (8)
 
 .SH SOURCES
- o IETF draft submission is at http://tools.ietf.org/html/draft-pan-tsvwg-pie-00
- o IEEE  Conference on High Performance Switching and Routing 2013 : "PIE: A
-Lightweight Control Scheme to Address the Bufferbloat Problem"
+ o RFC 8033: https://tools.ietf.org/html/rfc8033
 
 .SH AUTHORS
 PIE was implemented by Vijay Subramanian and Mythili Prabhu, also the authors of
diff --git a/man/man8/tc.8 b/man/man8/tc.8
index f98398a3..ab0bad8a 100644
--- a/man/man8/tc.8
+++ b/man/man8/tc.8
@@ -848,6 +848,7 @@ was written by Alexey N. Kuznetsov and added in Linux 2.2.
 .BR tc-mqprio (8),
 .BR tc-pfifo (8),
 .BR tc-pfifo_fast (8),
+.BR tc-pie (8),
 .BR tc-red (8),
 .BR tc-route (8),
 .BR tc-sfb (8),
-- 
2.17.1

Re: [PATCH iproute2 2/2] tc: pie: update man page

[Stephen Hemminger]

On Sun, 24 Mar 2019 00:18:35 +0530
Leslie Monis <lesliemonis@gmail.com> wrote:

> Update man page to reflect the changes made in Linux.
> 
> Signed-off-by: Leslie Monis <lesliemonis@gmail.com>

This one is fine. Please resubmit whole series.

Re: [PATCH iproute2 2/2] tc: pie: update man page

[Leslie Monis]

On Wed, Mar 27, 2019 at 07:54:58AM -0700, Stephen Hemminger wrote:
> On Sun, 24 Mar 2019 00:18:35 +0530
> Leslie Monis <lesliemonis@gmail.com> wrote:
> 
> > Update man page to reflect the changes made in Linux.
> > 
> > Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
> 
> This one is fine. Please resubmit whole series.

Thanks for the feedback. I shall resubmit the series.