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Handle different kernel clock resolutions 

[IPROUTE]: Handle different kernel clock resolutions

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
This commit is contained in:
Patrick McHardy 2007-03-04 20:15:03 +01:00 committed by Stephen Hemminger
parent bd29e35d9d
commit 147e1d4b5a
1 changed files with 19 additions and 7 deletions
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26
tc/tc_core.c
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@ -23,9 +23,8 @@
#include "tc_core.h"
static __u32 t2us=1;
static __u32 us2t=1;
static double tick_in_usec = 1;
static double clock_factor = 1;
int tc_core_time2big(long time)
{
@ -48,12 +47,12 @@ long tc_core_tick2time(long tick)
long tc_core_time2ktime(long time)
{
return time;
return time * clock_factor;
}
long tc_core_ktime2time(long ktime)
{
return ktime;
return ktime / clock_factor;
}
unsigned tc_calc_xmittime(unsigned rate, unsigned size)
@ -98,16 +97,29 @@ int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu,
int tc_core_init()
{
FILE *fp = fopen("/proc/net/psched", "r");
FILE *fp;
__u32 clock_res;
__u32 t2us;
__u32 us2t;
fp = fopen("/proc/net/psched", "r");
if (fp == NULL)
return -1;
if (fscanf(fp, "%08x%08x", &t2us, &us2t) != 2) {
if (fscanf(fp, "%08x%08x%08x", &t2us, &us2t, &clock_res) != 3) {
fclose(fp);
return -1;
}
fclose(fp);
tick_in_usec = (double)t2us/us2t;
/* compatibility hack: for old iproute binaries (ignoring
* the kernel clock resolution) the kernel advertises a
* tick multiplier of 1000 in case of nano-second resolution,
* which really is 1. */
if (clock_res == 1000000000)
t2us = us2t;
clock_factor = (double)clock_res / TIME_UNITS_PER_SEC;
tick_in_usec = (double)t2us / us2t * clock_factor;
return 0;
}