Re: [Qemu-devel] [PATCH v6 4/7] exec: [tcg] Use different TBs according to the vCPU's dynamic tracing state

[Richard Henderson <rth@twiddle.net>]

On 12/28/2016 10:41 AM, Lluís Vilanova wrote:
> Every vCPU now uses a separate set of TBs for each set of dynamic
> tracing event state values. Each set of TBs can be used by any number of
> vCPUs to maximize TB reuse when vCPUs have the same tracing state.
>
> This feature is later used by tracetool to optimize tracing of guest
> code events.
>
> The maximum number of TB sets is defined as 2^E, where E is the number
> of events that have the 'vcpu' property (their state is stored in
> CPUState->trace_dstate).
>
> For this to work, a change on the dynamic tracing state of a vCPU will
> force it to flush its virtual TB cache (which is only indexed by
> address), and fall back to the physical TB cache (which now contains the
> vCPU's dynamic tracing state as part of the hashing function).
>
> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
> ---
>  cpu-exec.c                |   26 +++++++++++++++++++++-----
>  include/exec/exec-all.h   |    5 +++++
>  include/exec/tb-hash-xx.h |    8 +++++++-
>  include/exec/tb-hash.h    |    5 +++--
>  include/qemu-common.h     |    3 +++
>  tests/qht-bench.c         |    2 +-
>  trace/control-target.c    |    3 +++
>  trace/control.h           |    3 +++
>  translate-all.c           |   16 ++++++++++++++--
>  9 files changed, 60 insertions(+), 11 deletions(-)


Reviewed-by: Richard Henderson <rth@twiddle.net>


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