[NET_SCHED]: Add support for nano-second clock resolution
Add support to nano-second clock resolution with ktime as clock source.
Since the ABI uses clock ticks in some places and all clock sources
previously used micro-second resolution, this changes the API. To
avoid breakage with old iproute versions, a clock multiplier of 1000
is advertised in /proc/net/psched, which keeps everything but HFSC
working properly (modulo integer overflows). New iproute versions
can detect support for nano-second resolution by reading the third
value in /proc/net/psched and ignore the multiplier.
Signed-off-by: Patrick McHardy <[EMAIL PROTECTED]>
---
commit 7978ac74b18bf1e9b01284a15ea5b54442005bb4
tree 0c1782e884f2c8e791b35df15901c9cc9e64513e
parent 8e4951375c3678b4720de46791c39064d8633fca
author Patrick McHardy <[EMAIL PROTECTED]> Fri, 02 Mar 2007 03:48:49 +0100
committer Patrick McHardy <[EMAIL PROTECTED]> Sun, 04 Mar 2007 19:54:04 +0100
include/net/pkt_sched.h | 13 ++++++++++---
net/sched/Kconfig | 17 +++++++++++++++++
net/sched/sch_api.c | 4 ++--
net/sched/sch_hfsc.c | 19 +++++++++++++------
4 files changed, 42 insertions(+), 11 deletions(-)
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index b25cc6c..84731cb 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -51,12 +51,19 @@ static inline void *qdisc_priv(struct Qd
typedef u64 psched_time_t;
typedef long psched_tdiff_t;
-#ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
-#include <linux/ktime.h>
-
+#ifdef CONFIG_NET_SCH_CLK_NSEC_RESOLUTION
+#define PSCHED_CLOCK_RESOLUTION NSEC_PER_SEC
+#define PSCHED_US2NS(x) (x)
+#define PSCHED_NS2US(x) (x)
+#else
+#define PSCHED_CLOCK_RESOLUTION USEC_PER_SEC
/* Avoid doing 64 bit divide by 1000 */
#define PSCHED_US2NS(x) ((s64)(x) << 10)
#define PSCHED_NS2US(x) ((x) >> 10)
+#endif
+
+#ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
+#include <linux/ktime.h>
#define PSCHED_GET_TIME(stamp) \
((stamp) = PSCHED_NS2US(ktime_to_ns(ktime_get())))
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index f4544dd..11f9bfd 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -102,6 +102,23 @@ config NET_SCH_CLK_CPU
endchoice
+config NET_SCH_CLK_NSEC_RESOLUTION
+ bool "Use nano-second resolution (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ depends on NET_SCH_CLK_GETTIMEOFDAY
+ help
+ This option enables nano-second resolution for the packet scheduler
+ clock source.
+
+ To take full advantage of the increased precision, an iproute version
+ using nano-seconds internally is needed.
+
+ Note: enabling the option might cause misbehaviour because of
+ integer overflows. It will also break HFSC unless a current
+ version of iproute is used.
+
+ If unsure, say N.
+
comment "Queueing/Scheduling"
config NET_SCH_CBQ
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 503db48..1a1652d 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1181,9 +1181,9 @@ static int psched_tick_per_us;
#ifdef CONFIG_PROC_FS
static int psched_show(struct seq_file *seq, void *v)
{
- seq_printf(seq, "%08x %08x %08x %08x\n",
+ seq_printf(seq, "%08x %08x %08lx %08x\n",
psched_tick_per_us, psched_us_per_tick,
- 1000000, HZ);
+ PSCHED_CLOCK_RESOLUTION, HZ);
return 0;
}
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 7df1003..79ccc27 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -383,7 +383,7 @@ cftree_update(struct hfsc_class *cl)
* Clock source resolution (CONFIG_NET_SCH_CLK_*)
* JIFFIES: for 48<=HZ<=1534 resolution is between 0.63us and 1.27us.
* CPU: resolution is between 0.5us and 1us.
- * GETTIMEOFDAY: resolution is 1.024us.
+ * GETTIMEOFDAY: resolution is 1.024us, 1ns with NET_SCH_CLK_NSEC_RESOLUTION.
*
* sm and ism are scaled in order to keep effective digits.
* SM_SHIFT and ISM_SHIFT are selected to keep at least 4 effective
@@ -395,18 +395,25 @@ cftree_update(struct hfsc_class *cl)
*
* bits/sec 100Kbps 1Mbps 10Mbps 100Mbps 1Gbps
* ------------+-------------------------------------------------------
+ * bytes/ns 12.5e-6 125e-6 1250e-6 12500e-6 125000e-6
* bytes/0.5us 6.25e-3 62.5e-3 625e-3 6250e-e 62500e-3
* bytes/us 12.5e-3 125e-3 1250e-3 12500e-3 125000e-3
* bytes/1.024us 12.8e-3 128e-3 1280e-3 12800e-3 128000e-3
* bytes/1.27us 15.875e-3 158.75e-3 1587.5e-3 15875e-3 158750e-3
*
+ * ns/byte 80000 8000 800 80 8
* 0.5us/byte 160 16 1.6 0.16 0.016
* us/byte 80 8 0.8 0.08 0.008
* 1.024us/byte 78.125 7.8125 0.78125 0.078125 0.0078125
* 1.27us/byte 63 6.3 0.63 0.063 0.0063
*/
-#define SM_SHIFT 20
-#define ISM_SHIFT 18
+#ifdef CONFIG_NET_SCH_CLK_NSEC_RESOLUTION
+#define SM_SHIFT 30
+#define ISM_SHIFT 8
+#else
+#define SM_SHIFT 20
+#define ISM_SHIFT 18
+#endif
#define SM_MASK ((1ULL << SM_SHIFT) - 1)
#define ISM_MASK ((1ULL << ISM_SHIFT) - 1)
@@ -476,8 +483,8 @@ d2dx(u32 d)
u64 dx;
dx = ((u64)d * PSCHED_JIFFIE2US(HZ));
- dx += USEC_PER_SEC - 1;
- do_div(dx, USEC_PER_SEC);
+ dx += PSCHED_CLOCK_RESOLUTION - 1;
+ do_div(dx, PSCHED_CLOCK_RESOLUTION);
return dx;
}
@@ -497,7 +504,7 @@ dx2d(u64 dx)
{
u64 d;
- d = dx * USEC_PER_SEC;
+ d = dx * PSCHED_CLOCK_RESOLUTION;
do_div(d, PSCHED_JIFFIE2US(HZ));
return (u32)d;
}
-
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