----- Mail original -----
> De: "Frederic Konrad" <fred.kon...@greensocs.com>
> À: "Sebastian Tanase" <sebastian.tan...@openwide.fr>, qemu-devel@nongnu.org
> Cc: kw...@redhat.com, "peter maydell" <peter.mayd...@linaro.org>,
> a...@alex.org.uk, wenchaoq...@gmail.com,
> quint...@redhat.com, m...@tls.msk.ru, m...@redhat.com, stefa...@redhat.com,
> arm...@redhat.com, lcapitul...@redhat.com,
> mich...@walle.cc, aligu...@amazon.com, crobi...@redhat.com,
> pbonz...@redhat.com, afaer...@suse.de, r...@twiddle.net
> Envoyé: Mardi 1 Juillet 2014 09:47:37
> Objet: Re: [Qemu-devel] [RFC PATCH V3 6/6] monitor: Add drift info to 'info
> jit'
>
> On 30/06/2014 15:59, Sebastian Tanase wrote:
> > Show in 'info jit' the current delay between the host clock
> > and the guest clock. In addition, print the maximum advance
> > and delay of the guest compared to the host.
> >
> > Signed-off-by: Sebastian Tanase <sebastian.tan...@openwide.fr>
> > Tested-by: Camille Bégué <camille.be...@openwide.fr>
> > ---
> > cpu-exec.c | 61
> > +++++++++++++++++++++++++++++++++++----------------
> > cpus.c | 17 ++++++++++++++
> > include/qemu-common.h | 5 +++++
> > monitor.c | 1 +
> > 4 files changed, 65 insertions(+), 19 deletions(-)
> >
> > diff --git a/cpu-exec.c b/cpu-exec.c
> > index 4a4533d..06809f2 100644
> > --- a/cpu-exec.c
> > +++ b/cpu-exec.c
> > @@ -104,25 +104,18 @@ static void init_delay_params(SyncClocks *sc,
> > int64_t realtime_clock_value,
> > const CPUState *cpu)
> > {
> > - static int64_t clocks_offset = -1;
> > - int64_t virtual_clock_value;
> > if (!icount_align_option) {
> > return;
> > }
> > - /* On x86 target architecture, the PIT reset function (called
> > - by qemu_system_reset) will end up calling qemu_clock_warp
> > - and then icount_warp_rt changing vm_clock_warp_start from 0
> > (initial
> > - value) to -1. This in turn will make us skip the initial
> > offset
> > - between the real and virtual clocks (initially virtual
> > clock is 0).
> > - Therefore we impose that the first time we run the cpu
> > - the host and virtual clocks should be aligned; we don't
> > alter any of
> > - the clocks, we just calculate the difference between them.
> > */
> > - virtual_clock_value = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> > - if (clocks_offset == -1) {
> > - clocks_offset = realtime_clock_value -
> > virtual_clock_value;
> > - }
> > - sc->diff_clk = virtual_clock_value - realtime_clock_value +
> > clocks_offset;
> > + sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
> > + realtime_clock_value + clocks_offset;
> > sc->original_instr_counter = cpu->icount_extra +
> > cpu->icount_decr.u16.low;
> > + if (sc->diff_clk < max_delay) {
> > + max_delay = sc->diff_clk;
> > + }
> > + if (sc->diff_clk > max_advance) {
> > + max_advance = sc->diff_clk;
> > + }
> > }
> > static void print_delay(InformDelay *indl, int64_t diff_clk)
> > {
> > @@ -160,10 +153,32 @@ static void init_inform(InformDelay *indl,
> > int64_t realtime_clock_value)
> >
> > static void compute_value_of_rtc(int64_t *realtime_clock_value)
> > {
> > - if (!icount_align_option) {
> > - return;
> > + /* When using align, we use every time the value of the host
> > clock
> > + whereas when not using align, we only need it once to
> > calculate
> > + the offset between the host and virtual clocks. We then use
> > this
> > + value to correctly print the delay between the 2 clocks
> > when using
> > + "info jit" in the monitor. */
> > + if (icount_align_option) {
> > + *realtime_clock_value =
> > qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
> > + } else if (*realtime_clock_value == 0) {
> > + *realtime_clock_value =
> > qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
> > + }
> Why not "||" both if as they finally do the same thing?
>
> Fred
>
Good catch, I'll fix this in V4.
Thanks,
Sebastian
> > +}
> > +
> > +static void compute_clocks_offset(int64_t realtime_clock_value)
> > +{
> > + /* On x86 target architecture, the PIT reset function (called
> > + by qemu_system_reset) will end up calling qemu_clock_warp
> > + and then icount_warp_rt changing vm_clock_warp_start from 0
> > (initial
> > + value) to -1. This in turn will make us skip the initial
> > offset
> > + between the real and virtual clocks (initially virtual
> > clock is 0).
> > + Therefore we suppose that the first time we run the cpu
> > + the host and virtual clocks should be aligned; we don't
> > alter any of
> > + the clocks, we just calculate the difference between them.
> > */
> > + if (clocks_offset == -1) {
> > + clocks_offset = realtime_clock_value -
> > + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> > }
> > - *realtime_clock_value =
> > qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
> > }
> > #else
> > /* We don't use the align feature for User emulation
> > @@ -189,6 +204,10 @@ static void init_inform(InformDelay *indl,
> > int64_t realtime_clock_value)
> > static void compute_value_of_rtc(int64_t *realtime_clock_value)
> > {
> > }
> > +
> > +static void compute_clocks_offset(int64_t realtime_clock_value)
> > +{
> > +}
> > #endif /* CONFIG USER ONLY */
> >
> > void cpu_loop_exit(CPUState *cpu)
> > @@ -396,7 +415,7 @@ int cpu_exec(CPUArchState *env)
> > uint8_t *tc_ptr;
> > uintptr_t next_tb;
> > /* Delay algorithm */
> > - int64_t realtime_clock_value;
> > + static int64_t realtime_clock_value;
> > static SyncClocks sc = {
> > .init_delay = init_delay_params,
> > .perform_align = align_clocks
> > @@ -465,6 +484,10 @@ int cpu_exec(CPUArchState *env)
> > /* Calculating the realtime is expensive so we do it once
> > here
> > and then pass this value around. */
> > compute_value_of_rtc(&realtime_clock_value);
> > + /* We calculate the clocks_offset here, the very first time
> > + we run the cpu; we do it here because it gives us the best
> > + accuracy. */
> > + compute_clocks_offset(realtime_clock_value);
> > /* Calculate difference between guest clock and host clock.
> > This delay includes the delay of the last cycle, so
> > what we have to do is sleep until it is 0. As for the
> > diff --git a/cpus.c b/cpus.c
> > index 312c2ee..9947d40 100644
> > --- a/cpus.c
> > +++ b/cpus.c
> > @@ -64,6 +64,9 @@
> > #endif /* CONFIG_LINUX */
> >
> > static CPUState *next_cpu;
> > +int64_t clocks_offset = -1;
> > +int64_t max_delay;
> > +int64_t max_advance;
> >
> > bool cpu_is_stopped(CPUState *cpu)
> > {
> > @@ -1512,3 +1515,17 @@ void qmp_inject_nmi(Error **errp)
> > error_set(errp, QERR_UNSUPPORTED);
> > #endif
> > }
> > +
> > +void dump_drift_info(FILE *f, fprintf_function cpu_fprintf)
> > +{
> > + cpu_fprintf(f, "Host - Guest clock %ld(ms)\n",
> > + (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) -
> > clocks_offset -
> > + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL))/SCALE_MS);
> > + if (icount_align_option) {
> > + cpu_fprintf(f, "Max guest delay %ld(ms)\n",
> > -max_delay/SCALE_MS);
> > + cpu_fprintf(f, "Max guest advance %ld(ms)\n",
> > max_advance/SCALE_MS);
> > + } else {
> > + cpu_fprintf(f, "Max guest delay NA\n");
> > + cpu_fprintf(f, "Max guest advance NA\n");
> > + }
> > +}
> > diff --git a/include/qemu-common.h b/include/qemu-common.h
> > index f568635..f86b27b 100644
> > --- a/include/qemu-common.h
> > +++ b/include/qemu-common.h
> > @@ -110,6 +110,11 @@ void configure_icount(QemuOpts *opts, Error
> > **errp);
> > extern int use_icount;
> > extern int icount_time_shift;
> > extern int icount_align_option;
> > +extern int64_t clocks_offset;
> > +/* drift information for info jit command */
> > +extern int64_t max_delay;
> > +extern int64_t max_advance;
> > +void dump_drift_info(FILE *f, fprintf_function cpu_fprintf);
> >
> > #include "qemu/osdep.h"
> > #include "qemu/bswap.h"
> > diff --git a/monitor.c b/monitor.c
> > index 799131b..23c5534 100644
> > --- a/monitor.c
> > +++ b/monitor.c
> > @@ -1047,6 +1047,7 @@ static void do_info_registers(Monitor *mon,
> > const QDict *qdict)
> > static void do_info_jit(Monitor *mon, const QDict *qdict)
> > {
> > dump_exec_info((FILE *)mon, monitor_fprintf);
> > + dump_drift_info((FILE *)mon, monitor_fprintf);
> > }
> >
> > static void do_info_history(Monitor *mon, const QDict *qdict)
>
>
