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[NET_SCHED]: Use ktime as clocksource

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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>
This commit is contained in:
Patrick McHardy
2007-03-16 01:18:42 -07:00
committed by David S. Miller
parent ddc7b8e32b
commit 641b9e0e8b
5 changed files with 19 additions and 315 deletions
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31
net/sched/sch_hfsc.c
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@@ -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