| Message ID | 20140716205055.929964640@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 16/07/2014 23:04, Thomas Gleixner ha scritto: > Convert the relevant base data right away to nanoseconds instead of > doing the conversion on every readout. Reduces text size by 160 bytes. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Gleb Natapov <gleb@kernel.org> > Cc: kvm@vger.kernel.org > --- > arch/x86/kvm/x86.c | 44 ++++++++++++++------------------------------ > 1 file changed, 14 insertions(+), 30 deletions(-) > > Index: tip/arch/x86/kvm/x86.c > =================================================================== > --- tip.orig/arch/x86/kvm/x86.c > +++ tip/arch/x86/kvm/x86.c > @@ -984,9 +984,8 @@ struct pvclock_gtod_data { > u32 shift; > } clock; > > - /* open coded 'struct timespec' */ > - u64 monotonic_time_snsec; > - time_t monotonic_time_sec; > + u64 boot_ns; > + u64 nsec_base; > }; > > static struct pvclock_gtod_data pvclock_gtod_data; > @@ -994,6 +993,9 @@ static struct pvclock_gtod_data pvclock_ > static void update_pvclock_gtod(struct timekeeper *tk) > { > struct pvclock_gtod_data *vdata = &pvclock_gtod_data; > + u64 boot_ns; > + > + boot_ns = ktime_to_ns(ktime_add(tk->base_mono, tk->offs_boot)); > > write_seqcount_begin(&vdata->seq); > > @@ -1004,17 +1006,8 @@ static void update_pvclock_gtod(struct t > vdata->clock.mult = tk->mult; > vdata->clock.shift = tk->shift; > > - vdata->monotonic_time_sec = tk->xtime_sec > - + tk->wall_to_monotonic.tv_sec; > - vdata->monotonic_time_snsec = tk->xtime_nsec > - + (tk->wall_to_monotonic.tv_nsec > - << tk->shift); > - while (vdata->monotonic_time_snsec >= > - (((u64)NSEC_PER_SEC) << tk->shift)) { > - vdata->monotonic_time_snsec -= > - ((u64)NSEC_PER_SEC) << tk->shift; > - vdata->monotonic_time_sec++; > - } > + vdata->boot_ns = boot_ns; > + vdata->nsec_base = tk->xtime_nsec; > > write_seqcount_end(&vdata->seq); > } > @@ -1371,23 +1364,22 @@ static inline u64 vgettsc(cycle_t *cycle > return v * gtod->clock.mult; > } > > -static int do_monotonic(struct timespec *ts, cycle_t *cycle_now) > +static int do_monotonic_boot(s64 *t, cycle_t *cycle_now) > { > + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; > unsigned long seq; > - u64 ns; > int mode; > - struct pvclock_gtod_data *gtod = &pvclock_gtod_data; > + u64 ns; > > - ts->tv_nsec = 0; > do { > seq = read_seqcount_begin(>od->seq); > mode = gtod->clock.vclock_mode; > - ts->tv_sec = gtod->monotonic_time_sec; > - ns = gtod->monotonic_time_snsec; > + ns = gtod->nsec_base; > ns += vgettsc(cycle_now); > ns >>= gtod->clock.shift; > + ns += gtod->boot_ns; > } while (unlikely(read_seqcount_retry(>od->seq, seq))); > - timespec_add_ns(ts, ns); > + *t = ns; > > return mode; > } > @@ -1395,19 +1387,11 @@ static int do_monotonic(struct timespec > /* returns true if host is using tsc clocksource */ > static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) > { > - struct timespec ts; > - > /* checked again under seqlock below */ > if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC) > return false; > > - if (do_monotonic(&ts, cycle_now) != VCLOCK_TSC) > - return false; > - > - monotonic_to_bootbased(&ts); > - *kernel_ns = timespec_to_ns(&ts); > - > - return true; > + return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC; > } > #endif > > > Acked-by: Paolo Bonzini <pbonzini@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: tip/arch/x86/kvm/x86.c =================================================================== --- tip.orig/arch/x86/kvm/x86.c +++ tip/arch/x86/kvm/x86.c @@ -984,9 +984,8 @@ struct pvclock_gtod_data { u32 shift; } clock; - /* open coded 'struct timespec' */ - u64 monotonic_time_snsec; - time_t monotonic_time_sec; + u64 boot_ns; + u64 nsec_base; }; static struct pvclock_gtod_data pvclock_gtod_data; @@ -994,6 +993,9 @@ static struct pvclock_gtod_data pvclock_ static void update_pvclock_gtod(struct timekeeper *tk) { struct pvclock_gtod_data *vdata = &pvclock_gtod_data; + u64 boot_ns; + + boot_ns = ktime_to_ns(ktime_add(tk->base_mono, tk->offs_boot)); write_seqcount_begin(&vdata->seq); @@ -1004,17 +1006,8 @@ static void update_pvclock_gtod(struct t vdata->clock.mult = tk->mult; vdata->clock.shift = tk->shift; - vdata->monotonic_time_sec = tk->xtime_sec - + tk->wall_to_monotonic.tv_sec; - vdata->monotonic_time_snsec = tk->xtime_nsec - + (tk->wall_to_monotonic.tv_nsec - << tk->shift); - while (vdata->monotonic_time_snsec >= - (((u64)NSEC_PER_SEC) << tk->shift)) { - vdata->monotonic_time_snsec -= - ((u64)NSEC_PER_SEC) << tk->shift; - vdata->monotonic_time_sec++; - } + vdata->boot_ns = boot_ns; + vdata->nsec_base = tk->xtime_nsec; write_seqcount_end(&vdata->seq); } @@ -1371,23 +1364,22 @@ static inline u64 vgettsc(cycle_t *cycle return v * gtod->clock.mult; } -static int do_monotonic(struct timespec *ts, cycle_t *cycle_now) +static int do_monotonic_boot(s64 *t, cycle_t *cycle_now) { + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; unsigned long seq; - u64 ns; int mode; - struct pvclock_gtod_data *gtod = &pvclock_gtod_data; + u64 ns; - ts->tv_nsec = 0; do { seq = read_seqcount_begin(>od->seq); mode = gtod->clock.vclock_mode; - ts->tv_sec = gtod->monotonic_time_sec; - ns = gtod->monotonic_time_snsec; + ns = gtod->nsec_base; ns += vgettsc(cycle_now); ns >>= gtod->clock.shift; + ns += gtod->boot_ns; } while (unlikely(read_seqcount_retry(>od->seq, seq))); - timespec_add_ns(ts, ns); + *t = ns; return mode; } @@ -1395,19 +1387,11 @@ static int do_monotonic(struct timespec /* returns true if host is using tsc clocksource */ static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) { - struct timespec ts; - /* checked again under seqlock below */ if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC) return false; - if (do_monotonic(&ts, cycle_now) != VCLOCK_TSC) - return false; - - monotonic_to_bootbased(&ts); - *kernel_ns = timespec_to_ns(&ts); - - return true; + return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC; } #endif
Convert the relevant base data right away to nanoseconds instead of doing the conversion on every readout. Reduces text size by 160 bytes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org --- arch/x86/kvm/x86.c | 44 ++++++++++++++------------------------------ 1 file changed, 14 insertions(+), 30 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html