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authorPatrick McHardy <kaber@trash.net>2007-03-16 01:18:42 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:26:04 -0700
commit641b9e0e8b7f96425da6ce98f3361e3af0baee29 (patch)
tree2315fed3b4fd9df52a52464b9b1ce1561d403a87 /net/sched
parentddc7b8e32b22fe8b45d306b7d99472d4b560add6 (diff)
downloadlinux-641b9e0e8b7f96425da6ce98f3361e3af0baee29.tar.bz2
[NET_SCHED]: Use ktime as clocksource
Get rid of the manual clock source selection mess and use ktime. Also use a scalar representation, which allows to clean up pkt_sched.h a bit more and results in less ktime_to_ns() calls in most cases. The PSCHED_US2JIFFIE/PSCHED_JIFFIE2US macros are implemented quite inefficient by this patch, following patches will convert all qdiscs to hrtimers and get rid of them entirely. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/Kconfig56
-rw-r--r--net/sched/sch_api.c77
-rw-r--r--net/sched/sch_hfsc.c31
3 files changed, 5 insertions, 159 deletions
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index f4544dd86476..475df8449be9 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -46,62 +46,6 @@ config NET_SCH_FIFO
if NET_SCHED
-choice
- prompt "Packet scheduler clock source"
- default NET_SCH_CLK_GETTIMEOFDAY
- ---help---
- Packet schedulers need a monotonic clock that increments at a static
- rate. The kernel provides several suitable interfaces, each with
- different properties:
-
- - high resolution (us or better)
- - fast to read (minimal locking, no i/o access)
- - synchronized on all processors
- - handles cpu clock frequency changes
-
- but nothing provides all of the above.
-
-config NET_SCH_CLK_JIFFIES
- bool "Timer interrupt"
- ---help---
- Say Y here if you want to use the timer interrupt (jiffies) as clock
- source. This clock source is fast, synchronized on all processors and
- handles cpu clock frequency changes, but its resolution is too low
- for accurate shaping except at very low speed.
-
-config NET_SCH_CLK_GETTIMEOFDAY
- bool "gettimeofday"
- ---help---
- Say Y here if you want to use gettimeofday as clock source. This clock
- source has high resolution, is synchronized on all processors and
- handles cpu clock frequency changes, but it is slow.
-
- Choose this if you need a high resolution clock source but can't use
- the CPU's cycle counter.
-
-# don't allow on SMP x86 because they can have unsynchronized TSCs.
-# gettimeofday is a good alternative
-config NET_SCH_CLK_CPU
- bool "CPU cycle counter"
- depends on ((X86_TSC || X86_64) && !SMP) || ALPHA || SPARC64 || PPC64 || IA64
- ---help---
- Say Y here if you want to use the CPU's cycle counter as clock source.
- This is a cheap and high resolution clock source, but on some
- architectures it is not synchronized on all processors and doesn't
- handle cpu clock frequency changes.
-
- The useable cycle counters are:
-
- x86/x86_64 - Timestamp Counter
- alpha - Cycle Counter
- sparc64 - %ticks register
- ppc64 - Time base
- ia64 - Interval Time Counter
-
- Choose this if your CPU's cycle counter is working properly.
-
-endchoice
-
comment "Queueing/Scheduling"
config NET_SCH_CBQ
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 4a927a5e1fa6..d71bf79eb80b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1175,15 +1175,12 @@ reclassify:
return -1;
}
-static int psched_us_per_tick = 1;
-static int psched_tick_per_us = 1;
-
#ifdef CONFIG_PROC_FS
static int psched_show(struct seq_file *seq, void *v)
{
seq_printf(seq, "%08x %08x %08x %08x\n",
- psched_tick_per_us, psched_us_per_tick,
- 1000000, HZ);
+ (u32)NSEC_PER_USEC, (u32)PSCHED_US2NS(1),
+ 1000000, HZ);
return 0;
}
@@ -1202,80 +1199,10 @@ static const struct file_operations psched_fops = {
};
#endif
-#ifdef CONFIG_NET_SCH_CLK_CPU
-psched_tdiff_t psched_clock_per_hz;
-int psched_clock_scale;
-EXPORT_SYMBOL(psched_clock_per_hz);
-EXPORT_SYMBOL(psched_clock_scale);
-
-psched_time_t psched_time_base;
-cycles_t psched_time_mark;
-EXPORT_SYMBOL(psched_time_mark);
-EXPORT_SYMBOL(psched_time_base);
-
-/*
- * Periodically adjust psched_time_base to avoid overflow
- * with 32-bit get_cycles(). Safe up to 4GHz CPU.
- */
-static void psched_tick(unsigned long);
-static DEFINE_TIMER(psched_timer, psched_tick, 0, 0);
-
-static void psched_tick(unsigned long dummy)
-{
- if (sizeof(cycles_t) == sizeof(u32)) {
- psched_time_t dummy_stamp;
- PSCHED_GET_TIME(dummy_stamp);
- psched_timer.expires = jiffies + 1*HZ;
- add_timer(&psched_timer);
- }
-}
-
-int __init psched_calibrate_clock(void)
-{
- psched_time_t stamp, stamp1;
- struct timeval tv, tv1;
- psched_tdiff_t delay;
- long rdelay;
- unsigned long stop;
-
- psched_tick(0);
- stop = jiffies + HZ/10;
- PSCHED_GET_TIME(stamp);
- do_gettimeofday(&tv);
- while (time_before(jiffies, stop)) {
- barrier();
- cpu_relax();
- }
- PSCHED_GET_TIME(stamp1);
- do_gettimeofday(&tv1);
-
- delay = PSCHED_TDIFF(stamp1, stamp);
- rdelay = tv1.tv_usec - tv.tv_usec;
- rdelay += (tv1.tv_sec - tv.tv_sec)*1000000;
- if (rdelay > delay)
- return -1;
- delay /= rdelay;
- psched_tick_per_us = delay;
- while ((delay>>=1) != 0)
- psched_clock_scale++;
- psched_us_per_tick = 1<<psched_clock_scale;
- psched_clock_per_hz = (psched_tick_per_us*(1000000/HZ))>>psched_clock_scale;
- return 0;
-}
-#endif
-
static int __init pktsched_init(void)
{
struct rtnetlink_link *link_p;
-#ifdef CONFIG_NET_SCH_CLK_CPU
- if (psched_calibrate_clock() < 0)
- return -1;
-#elif defined(CONFIG_NET_SCH_CLK_JIFFIES)
- psched_tick_per_us = HZ<<PSCHED_JSCALE;
- psched_us_per_tick = 1000000;
-#endif
-
link_p = rtnetlink_links[PF_UNSPEC];
/* Setup rtnetlink links. It is made here to avoid
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 407c6fb1ba14..f85cfba647f8 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -195,20 +195,6 @@ struct hfsc_sched
struct timer_list wd_timer; /* watchdog timer */
};
-/*
- * macros
- */
-#ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
-#include <linux/time.h>
-#undef PSCHED_GET_TIME
-#define PSCHED_GET_TIME(stamp) \
-do { \
- struct timeval tv; \
- do_gettimeofday(&tv); \
- (stamp) = 1ULL * USEC_PER_SEC * tv.tv_sec + tv.tv_usec; \
-} while (0)
-#endif
-
#define HT_INFINITY 0xffffffffffffffffULL /* infinite time value */
@@ -394,28 +380,17 @@ cftree_update(struct hfsc_class *cl)
* ism: (psched_us/byte) << ISM_SHIFT
* dx: psched_us
*
- * 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 exactly 1us.
+ * The clock source resolution with ktime is 1.024us.
*
* sm and ism are scaled in order to keep effective digits.
* SM_SHIFT and ISM_SHIFT are selected to keep at least 4 effective
* digits in decimal using the following table.
*
- * Note: We can afford the additional accuracy (altq hfsc keeps at most
- * 3 effective digits) thanks to the fact that linux clock is bounded
- * much more tightly.
- *
* bits/sec 100Kbps 1Mbps 10Mbps 100Mbps 1Gbps
* ------------+-------------------------------------------------------
- * 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/1.27us 15.875e-3 158.75e-3 1587.5e-3 15875e-3 158750e-3
+ * bytes/1.024us 12.8e-3 128e-3 1280e-3 12800e-3 128000e-3
*
- * 0.5us/byte 160 16 1.6 0.16 0.016
- * us/byte 80 8 0.8 0.08 0.008
- * 1.27us/byte 63 6.3 0.63 0.063 0.0063
+ * 1.024us/byte 78.125 7.8125 0.78125 0.078125 0.0078125
*/
#define SM_SHIFT 20
#define ISM_SHIFT 18