Re: [Qemu-devel] [PATCH 20/32] accel_trace_io

["andrzej zaborowski" <balrogg@gmail.com>]

2008/10/23 Glauber Costa <glommer@redhat.com>:
> From: Glauber Costa <gcosta@redhat.com>
>
> kqemu keeps trace of the last io done. Do it through
> an accel_wrapper.
>
> Signed-off-by: Glauber Costa <gcosta@redhat.com>
> ---
>  accel.c            |    2 ++
>  accel.h            |   13 ++++++++++++-
>  cpu-exec.c         |    9 ++-------
>  kqemu.c            |   18 ++++++++++++++++++
>  softmmu_template.h |   10 ++++------
>  vl.c               |   30 ++++++------------------------
>  6 files changed, 44 insertions(+), 38 deletions(-)
>
> diff --git a/accel.c b/accel.c
> index bf1194d..0890039 100644
> --- a/accel.c
> +++ b/accel.c
> @@ -32,5 +32,7 @@ QEMUAccel noaccel = {
>     .get_real_ticks = cpu_get_ticks,
>  #endif
>     .register_physical_memory = accel_nop,
> +    .trace_io = accel_nop,
> +    .break_loop = accel_nop,
>  };
>
> diff --git a/accel.h b/accel.h
> index dbb6372..b37175b 100644
> --- a/accel.h
> +++ b/accel.h
> @@ -19,7 +19,8 @@ typedef struct QEMUAccel {
>  #endif
>     void (*register_physical_memory)(uint64_t start_addr,
>                                      ram_addr_t size, ram_addr_t phys_offset);
> -
> +    void (*trace_io)(CPUState *env);
> +    int (*break_loop)(CPUState *env);
>  } QEMUAccel;
>
>  typedef struct QEMUCont {
> @@ -142,4 +143,14 @@ static inline void accel_register_phys_mem(uint64_t start_addr,
>  {
>     current_accel->register_physical_memory(start_addr, size, phys_offset);
>  }
> +
> +static inline void accel_trace_io(CPUState *env)
> +{
> +    current_accel->trace_io(env);
> +}
> +
> +static inline int accel_break_loop(CPUState *env)
> +{
> +    return current_accel->break_loop(env);
> +}
>  #endif
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 88b7d6f..18908d5 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -36,6 +36,7 @@
>  #include <signal.h>
>  #include <sys/ucontext.h>
>  #endif
> +#include "accel.h"
>
>  #if defined(__sparc__) && !defined(HOST_SOLARIS)
>  // Work around ugly bugs in glibc that mangle global register contents
> @@ -646,13 +647,7 @@ int cpu_exec(CPUState *env1)
>                 }
>                 /* reset soft MMU for next block (it can currently
>                    only be set by a memory fault) */
> -#if defined(USE_KQEMU)
> -#define MIN_CYCLE_BEFORE_SWITCH (100 * 1000)
> -                if (kqemu_is_ok(env) &&
> -                    (cpu_get_time_fast() - env->last_io_time) >= MIN_CYCLE_BEFORE_SWITCH) {
> -                    cpu_loop_exit();
> -                }
> -#endif
> +                accel_break_loop(env);
>             } /* for(;;) */
>         } else {
>             env_to_regs();
> diff --git a/kqemu.c b/kqemu.c
> index f4d905a..d38d0e3 100644
> --- a/kqemu.c
> +++ b/kqemu.c
> @@ -1107,6 +1107,22 @@ static int kqemu_profile(CPUState *env, char *buf)
>     return len;
>  }
>
> +static void kqemu_trace_io(CPUState *env)
> +{
> +    if (env)
> +        env->last_io_time = cpu_get_time_fast();
> +}
> +
> +static int kqemu_break_loop(CPUState *env)
> +{
> +#define MIN_CYCLE_BEFORE_SWITCH (100 * 1000)
> +    if (kqemu_is_ok(env) &&
> +        (cpu_get_time_fast() - env->last_io_time) >= MIN_CYCLE_BEFORE_SWITCH) {
> +        return 1;
> +    }
> +    return 0;
> +}
> +
>  QEMUAccel kqemu_accel = {
>     .name = "KQEMU",
>     .cpu_interrupt = kqemu_cpu_interrupt,
> @@ -1125,6 +1141,8 @@ QEMUAccel kqemu_accel = {
>     .get_real_ticks = cpu_get_real_ticks,
>  #endif
>     .register_physical_memory = kqemu_set_phys_mem,
> +    .trace_io = kqemu_trace_io,
> +    .break_loop = kqemu_break_loop,
>  };
>
>  #endif
> diff --git a/softmmu_template.h b/softmmu_template.h
> index 98dd378..4945352 100644
> --- a/softmmu_template.h
> +++ b/softmmu_template.h
> @@ -47,6 +47,8 @@
>  #define ADDR_READ addr_read
>  #endif
>
> +#include "accel.h"
> +
>  static DATA_TYPE glue(glue(slow_ld, SUFFIX), MMUSUFFIX)(target_ulong addr,
>                                                         int mmu_idx,
>                                                         void *retaddr);
> @@ -75,9 +77,7 @@ static inline DATA_TYPE glue(io_read, SUFFIX)(target_phys_addr_t physaddr,
>     res |= (uint64_t)io_mem_read[index][2](io_mem_opaque[index], physaddr + 4) << 32;
>  #endif
>  #endif /* SHIFT > 2 */
> -#ifdef USE_KQEMU
> -    env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>     return res;
>  }
>
> @@ -220,9 +220,7 @@ static inline void glue(io_write, SUFFIX)(target_phys_addr_t physaddr,
>     io_mem_write[index][2](io_mem_opaque[index], physaddr + 4, val >> 32);
>  #endif
>  #endif /* SHIFT > 2 */
> -#ifdef USE_KQEMU
> -    env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>  }
>
>  void REGPARM glue(glue(__st, SUFFIX), MMUSUFFIX)(target_ulong addr,
> diff --git a/vl.c b/vl.c
> index 964205d..e64becb 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -420,10 +420,7 @@ void cpu_outb(CPUState *env, int addr, int val)
>         fprintf(logfile, "outb: %04x %02x\n", addr, val);
>  #endif
>     ioport_write(0, addr, val);
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>  }
>
>  void cpu_outw(CPUState *env, int addr, int val)
> @@ -433,10 +430,7 @@ void cpu_outw(CPUState *env, int addr, int val)
>         fprintf(logfile, "outw: %04x %04x\n", addr, val);
>  #endif
>     ioport_write(1, addr, val);
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>  }
>
>  void cpu_outl(CPUState *env, int addr, int val)
> @@ -446,10 +440,7 @@ void cpu_outl(CPUState *env, int addr, int val)
>         fprintf(logfile, "outl: %04x %08x\n", addr, val);
>  #endif
>     ioport_write(2, addr, val);
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>  }
>
>  int cpu_inb(CPUState *env, int addr)
> @@ -460,10 +451,7 @@ int cpu_inb(CPUState *env, int addr)
>     if (loglevel & CPU_LOG_IOPORT)
>         fprintf(logfile, "inb : %04x %02x\n", addr, val);
>  #endif
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>     return val;
>  }
>
> @@ -475,10 +463,7 @@ int cpu_inw(CPUState *env, int addr)
>     if (loglevel & CPU_LOG_IOPORT)
>         fprintf(logfile, "inw : %04x %04x\n", addr, val);
>  #endif
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);
>     return val;
>  }
>
> @@ -490,10 +475,7 @@ int cpu_inl(CPUState *env, int addr)
>     if (loglevel & CPU_LOG_IOPORT)
>         fprintf(logfile, "inl : %04x %08x\n", addr, val);
>  #endif
> -#ifdef USE_KQEMU
> -    if (env)
> -        env->last_io_time = cpu_get_time_fast();
> -#endif
> +    accel_trace_io(env);

It would be great if all the new checks on the critical paths could
remain wrapped in some kind of #ifdef for archs that don't have any
acceleration implemented (also in other patches in this series).

[skipped a rant about the explosion of correctness fixes and clean-up
and some guests in practice booting nearly 2x slower compared to a
last year's qemu snapshot]

Regards