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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-07-12 22:49:59 +0400
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-08-05 01:47:29 +0400
commit8a22b9996b001c88f2bfb54c6de6a05fc39e177a (patch)
treefaf40add399c0652c7d2b2cdf0f01d805a91e207 /arch/x86/xen/time.c
parent31de189f7d02da163f77d46a86d9e655a2d83124 (diff)
downloadlinux-8a22b9996b001c88f2bfb54c6de6a05fc39e177a.tar.xz
xen: drop xen_sched_clock in favour of using plain wallclock time
xen_sched_clock only counts unstolen time. In principle this should be useful to the Linux scheduler so that it knows how much time a process actually consumed. But in practice this doesn't work very well as the scheduler expects the sched_clock time to be synchronized between cpus. It also uses sched_clock to measure the time a task spends sleeping, in which case "unstolen time" isn't meaningful. So just use plain xen_clocksource_read to return wallclock nanoseconds for sched_clock. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'arch/x86/xen/time.c')
-rw-r--r--arch/x86/xen/time.c39
1 files changed, 0 insertions, 39 deletions
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 32764b8880b5..e90360ff4a08 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -155,45 +155,6 @@ static void do_stolen_accounting(void)
account_idle_ticks(ticks);
}
-/*
- * Xen sched_clock implementation. Returns the number of unstolen
- * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
- * states.
- */
-unsigned long long xen_sched_clock(void)
-{
- struct vcpu_runstate_info state;
- cycle_t now;
- u64 ret;
- s64 offset;
-
- /*
- * Ideally sched_clock should be called on a per-cpu basis
- * anyway, so preempt should already be disabled, but that's
- * not current practice at the moment.
- */
- preempt_disable();
-
- now = xen_clocksource_read();
-
- get_runstate_snapshot(&state);
-
- WARN_ON(state.state != RUNSTATE_running);
-
- offset = now - state.state_entry_time;
- if (offset < 0)
- offset = 0;
-
- ret = state.time[RUNSTATE_blocked] +
- state.time[RUNSTATE_running] +
- offset;
-
- preempt_enable();
-
- return ret;
-}
-
-
/* Get the TSC speed from Xen */
unsigned long xen_tsc_khz(void)
{