Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Alex, On Fri, Apr 28, 2023 at 11:43:26AM +0200, Aleksandar Lazic wrote: > Attached the new patch. Thank you, it went OK on the CI so we don't even need to refine the list of targets for now. I've just merged it as-is. Many thanks for your fast update and for the reminder! Willy
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Willy.
On 28.04.23 11:14, Aleksandar Lazic wrote:
Hi Will.
On 28.04.23 11:07, Willy Tarreau wrote:
[snipp]
So from what I'm reading above, the regtest is fake and doesn't test
the presence of digits in the returned value. Could you please correct
it so that it properly verifies that your patch works, and then I'm
fine with merging it.
Okay will take a look and create a new patch.
Attached the new patch.
Regards
AlexFrom 01b0561f0aad6ecf14e1bef552d9c2ad66ad1d67 Mon Sep 17 00:00:00 2001
From: Aleksandar Lazic
Date: Fri, 28 Apr 2023 11:39:12 +0200
Subject: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
This Patch adds fetch samples for backends round trip time.
---
doc/configuration.txt| 16 ++
reg-tests/sample_fetches/tcpinfo_rtt.vtc | 39
src/tcp_sample.c | 32 +++
3 files changed, 87 insertions(+)
create mode 100644 reg-tests/sample_fetches/tcpinfo_rtt.vtc
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 32d2fec17..28f308f9d 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -19642,6 +19642,22 @@ be_name : string
frontends with responses to check which backend processed the request. It can
also be used in a tcp-check or an http-check ruleset.
+bc_rtt() : integer
+ Returns the Round Trip Time (RTT) measured by the kernel for the backend
+ connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the server
+ connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
+bc_rttvar() : integer
+ Returns the Round Trip Time (RTT) variance measured by the kernel for the
+ backend connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the
+ server connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
be_server_timeout : integer
Returns the configuration value in millisecond for the server timeout of the
current backend. This timeout can be overwritten by a "set-timeout" rule. See
diff --git a/reg-tests/sample_fetches/tcpinfo_rtt.vtc b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
new file mode 100644
index 0..93300d528
--- /dev/null
+++ b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
@@ -0,0 +1,39 @@
+varnishtest "Test declaration of TCP rtt fetches"
+
+# feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(v2.8-dev8)'"
+feature ignore_unknown_macro
+
+server s1 {
+rxreq
+txresp
+} -start
+
+haproxy h1 -conf {
+ defaults common
+ mode http
+ timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout client "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout server "${HAPROXY_TEST_TIMEOUT-5s}"
+
+ frontend fe from common
+ bind "fd@${feh1}"
+
+ default_backend be
+
+ backend be from common
+
+ http-response set-header x-test1 "%[fc_rtt]"
+ http-response set-header x-test2 "%[bc_rtt(us)]"
+ http-response set-header x-test3 "%[fc_rttvar]"
+ http-response set-header x-test4 "%[bc_rttvar]"
+
+ server s1 ${s1_addr}:${s1_port}
+
+} -start
+
+client c1 -connect ${h1_feh1_sock} {
+txreq -req GET -url /
+rxresp
+expect resp.status == 200
+expect resp.http.x-test2 ~ "[0-9]+"
+} -run
\ No newline at end of file
diff --git a/src/tcp_sample.c b/src/tcp_sample.c
index 12eb25c4e..393e39e93 100644
--- a/src/tcp_sample.c
+++ b/src/tcp_sample.c
@@ -401,6 +401,35 @@ smp_fetch_fc_rttvar(const struct arg *args, struct sample *smp, const char *kw,
return 1;
}
+/* get the mean rtt of a backend connection */
+static int
+smp_fetch_bc_rtt(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 0))
+ return 0;
+
+ /* By default or if explicitly specified, convert rtt to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0].data.sint == TIME_UNIT_MS)
+ smp->data.u.sint = (smp->data.u.sint + 500) / 1000;
+
+ return 1;
+}
+
+/* get the variance of the mean rtt of a backend connection */
+static int
+smp_fetch_bc_rttvar(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 1))
+ return 0;
+
+ /* By default or if explicitly specified, convert rttvar to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0].data.sint == TIME_UNIT_MS)
+ smp->data.u.sint = (smp->data.u.sint + 500) / 1000;
+
+ return 1;
+}
+
+
#if defined(__linux__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__Ope
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Will. On 28.04.23 11:07, Willy Tarreau wrote: Hi Alex, On Fri, Apr 28, 2023 at 10:59:46AM +0200, Aleksandar Lazic wrote: Hi Willy. On 30.03.23 06:23, Willy Tarreau wrote: On Thu, Mar 30, 2023 at 06:16:34AM +0200, Willy Tarreau wrote: Hi Alex, On Wed, Mar 29, 2023 at 04:06:10PM +0200, Aleksandar Lazic wrote: Ping? thanks for the ping, I missed it a few times when being busy with some painful bugs in the past. I've pushed it to a topic branch to verify what it does on the CI for non-linux OS; we might have to add a "feature cmd" filter in the regtest to check for linux, and I don't think we directly have this right now (though we could rely on LINUX_SPLICE for now as a proxy). Or even simpler, we still have the ability to use "EXCLUDE_TARGETS=freebsd,osx,generic" so I may adapt your regtest to that as well if it fails on the CI. Ah so... it passes because we have TCP_INFO on macos as well, and on Windows we don't run vtest. However the "expect" rule is only for a status code 200 :-) I think it would be nice to check for the presence of digits in these 4 headers. I'll try to do it as time permits but if you beat me to it I'll take your proposal! I'm not sure if I get you answer. Do you need another patch from me? Damn, I continue to forget about this one :-( Actually it's extremely difficult for me to dedicate time to modify stuff that I didn't create because it's not in my radar. So from what I'm reading above, the regtest is fake and doesn't test the presence of digits in the returned value. Could you please correct it so that it properly verifies that your patch works, and then I'm fine with merging it. Okay will take a look and create a new patch. Thank you! Willy Regards Alex
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Alex, On Fri, Apr 28, 2023 at 10:59:46AM +0200, Aleksandar Lazic wrote: > Hi Willy. > > On 30.03.23 06:23, Willy Tarreau wrote: > > On Thu, Mar 30, 2023 at 06:16:34AM +0200, Willy Tarreau wrote: > > > Hi Alex, > > > > > > On Wed, Mar 29, 2023 at 04:06:10PM +0200, Aleksandar Lazic wrote: > > > > Ping? > > > > > > thanks for the ping, I missed it a few times when being busy with some > > > painful bugs in the past. I've pushed it to a topic branch to verify > > > what it does on the CI for non-linux OS; we might have to add a > > > "feature cmd" filter in the regtest to check for linux, and I don't > > > think we directly have this right now (though we could rely on > > > LINUX_SPLICE for now as a proxy). Or even simpler, we still have > > > the ability to use "EXCLUDE_TARGETS=freebsd,osx,generic" so I may > > > adapt your regtest to that as well if it fails on the CI. > > > > Ah so... it passes because we have TCP_INFO on macos as well, and on > > Windows we don't run vtest. However the "expect" rule is only for a > > status code 200 :-) I think it would be nice to check for the presence > > of digits in these 4 headers. I'll try to do it as time permits but if > > you beat me to it I'll take your proposal! > > I'm not sure if I get you answer. > Do you need another patch from me? Damn, I continue to forget about this one :-( Actually it's extremely difficult for me to dedicate time to modify stuff that I didn't create because it's not in my radar. So from what I'm reading above, the regtest is fake and doesn't test the presence of digits in the returned value. Could you please correct it so that it properly verifies that your patch works, and then I'm fine with merging it. Thank you! Willy
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Willy. On 30.03.23 06:23, Willy Tarreau wrote: On Thu, Mar 30, 2023 at 06:16:34AM +0200, Willy Tarreau wrote: Hi Alex, On Wed, Mar 29, 2023 at 04:06:10PM +0200, Aleksandar Lazic wrote: Ping? thanks for the ping, I missed it a few times when being busy with some painful bugs in the past. I've pushed it to a topic branch to verify what it does on the CI for non-linux OS; we might have to add a "feature cmd" filter in the regtest to check for linux, and I don't think we directly have this right now (though we could rely on LINUX_SPLICE for now as a proxy). Or even simpler, we still have the ability to use "EXCLUDE_TARGETS=freebsd,osx,generic" so I may adapt your regtest to that as well if it fails on the CI. Ah so... it passes because we have TCP_INFO on macos as well, and on Windows we don't run vtest. However the "expect" rule is only for a status code 200 :-) I think it would be nice to check for the presence of digits in these 4 headers. I'll try to do it as time permits but if you beat me to it I'll take your proposal! I'm not sure if I get you answer. Do you need another patch from me? Thanks, Willy Regards Alex
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
On Thu, Mar 30, 2023 at 06:16:34AM +0200, Willy Tarreau wrote: > Hi Alex, > > On Wed, Mar 29, 2023 at 04:06:10PM +0200, Aleksandar Lazic wrote: > > Ping? > > thanks for the ping, I missed it a few times when being busy with some > painful bugs in the past. I've pushed it to a topic branch to verify > what it does on the CI for non-linux OS; we might have to add a > "feature cmd" filter in the regtest to check for linux, and I don't > think we directly have this right now (though we could rely on > LINUX_SPLICE for now as a proxy). Or even simpler, we still have > the ability to use "EXCLUDE_TARGETS=freebsd,osx,generic" so I may > adapt your regtest to that as well if it fails on the CI. Ah so... it passes because we have TCP_INFO on macos as well, and on Windows we don't run vtest. However the "expect" rule is only for a status code 200 :-) I think it would be nice to check for the presence of digits in these 4 headers. I'll try to do it as time permits but if you beat me to it I'll take your proposal! Thanks, Willy
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi Alex, On Wed, Mar 29, 2023 at 04:06:10PM +0200, Aleksandar Lazic wrote: > Ping? thanks for the ping, I missed it a few times when being busy with some painful bugs in the past. I've pushed it to a topic branch to verify what it does on the CI for non-linux OS; we might have to add a "feature cmd" filter in the regtest to check for linux, and I don't think we directly have this right now (though we could rely on LINUX_SPLICE for now as a proxy). Or even simpler, we still have the ability to use "EXCLUDE_TARGETS=freebsd,osx,generic" so I may adapt your regtest to that as well if it fails on the CI. Thanks! Willy
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Ping? On 10.01.23 21:27, Aleksandar Lazic wrote: On 09.12.22 13:17, Aleksandar Lazic wrote: Hi. As I still think that the Balancing algorithm (Peak) EWMA ( https://github.com/haproxy/haproxy/issues/1570 ) could help to make a "better" decision to which server should the request be send, here the beginning of the patches. In any cases it would be nice to know the rtt from the backend, Imho. Does anybody know how I can "delay/sleep/wait" for the server answer to get some rtt which are not 0 as the rtt is 0. Here the updated Patch without the EWMA reference. Regards Alex
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi. Any chance to add this Patch? Regards Alex On 10.01.23 21:27, Aleksandar Lazic wrote: On 09.12.22 13:17, Aleksandar Lazic wrote: Hi. As I still think that the Balancing algorithm (Peak) EWMA ( https://github.com/haproxy/haproxy/issues/1570 ) could help to make a "better" decision to which server should the request be send, here the beginning of the patches. In any cases it would be nice to know the rtt from the backend, Imho. Does anybody know how I can "delay/sleep/wait" for the server answer to get some rtt which are not 0 as the rtt is 0. Here the updated Patch without the EWMA reference. Regards Alex
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
On 09.12.22 13:17, Aleksandar Lazic wrote:
Hi.
As I still think that the Balancing algorithm (Peak) EWMA (
https://github.com/haproxy/haproxy/issues/1570 ) could help to make a
"better" decision to which server should the request be send, here the
beginning of the patches.
In any cases it would be nice to know the rtt from the backend, Imho.
Does anybody know how I can "delay/sleep/wait" for the server answer to
get some rtt which are not 0 as the rtt is 0.
Here the updated Patch without the EWMA reference.
Regards
AlexFrom 7610bb7234bd324e06e56732a67bf8a0e65d7dbc Mon Sep 17 00:00:00 2001
From: Aleksandar Lazic
Date: Fri, 9 Dec 2022 13:05:52 +0100
Subject: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
This Patch adds the fetch sample for backends round trip time.
---
doc/configuration.txt| 16 ++
reg-tests/sample_fetches/tcpinfo_rtt.vtc | 39
src/tcp_sample.c | 33
3 files changed, 88 insertions(+)
create mode 100644 reg-tests/sample_fetches/tcpinfo_rtt.vtc
diff --git a/doc/configuration.txt b/doc/configuration.txt
index c45f0b4b6..e8526de7f 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -18854,6 +18854,22 @@ be_server_timeout : integer
current backend. This timeout can be overwritten by a "set-timeout" rule. See
also the "cur_server_timeout".
+bc_rtt() : integer
+ Returns the Round Trip Time (RTT) measured by the kernel for the backend
+ connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the server
+ connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
+bc_rttvar() : integer
+ Returns the Round Trip Time (RTT) variance measured by the kernel for the
+ backend connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the
+ server connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
be_tunnel_timeout : integer
Returns the configuration value in millisecond for the tunnel timeout of the
current backend. This timeout can be overwritten by a "set-timeout" rule. See
diff --git a/reg-tests/sample_fetches/tcpinfo_rtt.vtc b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
new file mode 100644
index 0..f28a2072e
--- /dev/null
+++ b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
@@ -0,0 +1,39 @@
+varnishtest "Test declaration of TCP rtt fetches"
+
+# feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(v2.8-dev1)'"
+feature ignore_unknown_macro
+
+server s1 {
+rxreq
+txresp
+} -start
+
+haproxy h1 -conf {
+ defaults common
+ mode http
+ timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout client "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout server "${HAPROXY_TEST_TIMEOUT-5s}"
+
+ frontend fe from common
+ bind "fd@${feh1}"
+
+ default_backend be
+
+ backend be from common
+
+ http-response set-header x-test1 "%[fc_rtt]"
+ http-response set-header x-test2 "%[bc_rtt]"
+ http-response set-header x-test3 "%[fc_rttvar]"
+ http-response set-header x-test4 "%[bc_rttvar]"
+
+ server s1 ${s1_addr}:${s1_port}
+
+} -start
+
+client c1 -connect ${h1_feh1_sock} {
+txreq -req GET -url /
+rxresp
+expect resp.status == 200
+#expect resp.http.x-test2 ~ " ms"
+} -run
diff --git a/src/tcp_sample.c b/src/tcp_sample.c
index 925b93291..bf0d538ea 100644
--- a/src/tcp_sample.c
+++ b/src/tcp_sample.c
@@ -373,6 +373,34 @@ static inline int get_tcp_info(const struct arg *args, struct sample *smp,
return 1;
}
+/* get the mean rtt of a backend/server connection */
+static int
+smp_fetch_bc_rtt(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 0))
+ return 0;
+
+ /* By default or if explicitly specified, convert rtt to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0].data.sint == TIME_UNIT_MS)
+ smp->data.u.sint = (smp->data.u.sint + 500) / 1000;
+
+ return 1;
+}
+
+/* get the variance of the mean rtt of a backend/server connection */
+static int
+smp_fetch_bc_rttvar(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 1))
+ return 0;
+
+ /* By default or if explicitly specified, convert rttvar to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0].data.sint == TIME_UNIT_MS)
+ smp->data.u.sint = (smp->data.u.sint + 500) /
Re: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi, Any feedback to that patch? On 09.12.22 13:17, Aleksandar Lazic wrote: Hi. As I still think that the Balancing algorithm (Peak) EWMA ( https://github.com/haproxy/haproxy/issues/1570 ) could help to make a "better" decision to which server should the request be send, here the beginning of the patches. In any cases it would be nice to know the rtt from the backend, Imho. Does anybody know how I can "delay/sleep/wait" for the server answer to get some rtt which are not 0 as the rtt is 0. Regards Alex
[PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
Hi.
As I still think that the Balancing algorithm (Peak) EWMA (
https://github.com/haproxy/haproxy/issues/1570 ) could help to make a
"better" decision to which server should the request be send, here the
beginning of the patches.
In any cases it would be nice to know the rtt from the backend, Imho.
Does anybody know how I can "delay/sleep/wait" for the server answer to
get some rtt which are not 0 as the rtt is 0.
Regards
AlexFrom 7610bb7234bd324e06e56732a67bf8a0e65d7dbc Mon Sep 17 00:00:00 2001
From: Aleksandar Lazic
Date: Fri, 9 Dec 2022 13:05:52 +0100
Subject: [PATCH] MINOR: sample: Add bc_rtt and bc_rttvar
To be able to implement "Balancing algorithm (Peak) EWMA" is it
necessary to know the round trip time to the backend.
This Patch adds the fetch sample for the backend server.
Part of GH https://github.com/haproxy/haproxy/issues/1570
---
doc/configuration.txt| 16 ++
reg-tests/sample_fetches/tcpinfo_rtt.vtc | 39
src/tcp_sample.c | 33
3 files changed, 88 insertions(+)
create mode 100644 reg-tests/sample_fetches/tcpinfo_rtt.vtc
diff --git a/doc/configuration.txt b/doc/configuration.txt
index c45f0b4b6..e8526de7f 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -18854,6 +18854,22 @@ be_server_timeout : integer
current backend. This timeout can be overwritten by a "set-timeout" rule. See
also the "cur_server_timeout".
+bc_rtt() : integer
+ Returns the Round Trip Time (RTT) measured by the kernel for the backend
+ connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the server
+ connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
+bc_rttvar() : integer
+ Returns the Round Trip Time (RTT) variance measured by the kernel for the
+ backend connection. is facultative, by default the unit is milliseconds.
+ can be set to "ms" for milliseconds or "us" for microseconds. If the
+ server connection is not established, if the connection is not TCP or if the
+ operating system does not support TCP_INFO, for example Linux kernels before
+ 2.4, the sample fetch fails.
+
be_tunnel_timeout : integer
Returns the configuration value in millisecond for the tunnel timeout of the
current backend. This timeout can be overwritten by a "set-timeout" rule. See
diff --git a/reg-tests/sample_fetches/tcpinfo_rtt.vtc b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
new file mode 100644
index 0..f28a2072e
--- /dev/null
+++ b/reg-tests/sample_fetches/tcpinfo_rtt.vtc
@@ -0,0 +1,39 @@
+varnishtest "Test declaration of TCP rtt fetches"
+
+# feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(v2.8-dev1)'"
+feature ignore_unknown_macro
+
+server s1 {
+rxreq
+txresp
+} -start
+
+haproxy h1 -conf {
+ defaults common
+ mode http
+ timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout client "${HAPROXY_TEST_TIMEOUT-5s}"
+ timeout server "${HAPROXY_TEST_TIMEOUT-5s}"
+
+ frontend fe from common
+ bind "fd@${feh1}"
+
+ default_backend be
+
+ backend be from common
+
+ http-response set-header x-test1 "%[fc_rtt]"
+ http-response set-header x-test2 "%[bc_rtt]"
+ http-response set-header x-test3 "%[fc_rttvar]"
+ http-response set-header x-test4 "%[bc_rttvar]"
+
+ server s1 ${s1_addr}:${s1_port}
+
+} -start
+
+client c1 -connect ${h1_feh1_sock} {
+txreq -req GET -url /
+rxresp
+expect resp.status == 200
+#expect resp.http.x-test2 ~ " ms"
+} -run
diff --git a/src/tcp_sample.c b/src/tcp_sample.c
index 925b93291..bf0d538ea 100644
--- a/src/tcp_sample.c
+++ b/src/tcp_sample.c
@@ -373,6 +373,34 @@ static inline int get_tcp_info(const struct arg *args, struct sample *smp,
return 1;
}
+/* get the mean rtt of a backend/server connection */
+static int
+smp_fetch_bc_rtt(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 0))
+ return 0;
+
+ /* By default or if explicitly specified, convert rtt to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0].data.sint == TIME_UNIT_MS)
+ smp->data.u.sint = (smp->data.u.sint + 500) / 1000;
+
+ return 1;
+}
+
+/* get the variance of the mean rtt of a backend/server connection */
+static int
+smp_fetch_bc_rttvar(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+ if (!get_tcp_info(args, smp, 1, 1))
+ return 0;
+
+ /* By default or if explicitly specified, convert rttvar to ms */
+ if (!args || args[0].type == ARGT_STOP || args[0]
