Re: [Qemu-devel] [PATCH v1 2/3] cpus: dump TLB flush counts as trace event

[Paolo Bonzini]

On 11/04/2017 18:50, Alex Bennée wrote:
> This can be pre-processed later from the trace file.

What about skipping this patch, and instead adding five trace points

trace_tlb_flush_self(int vcpu)
trace_tlb_flush_async_schedule(int from, int to)
trace_tlb_flush_async_work(int vcpu)
trace_tlb_flush_synced_schedule(int vcpu)
trace_tlb_flush_synced_work(int vcpu)

The disadvantage is that the TLB flush counts are not emitted in "info
tcg", but the resulting information is finer-grained and the offline
accumulation of tracepoints can provide the same information.

Paolo

> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  cpus.c       | 6 ++++++
>  trace-events | 3 +++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/cpus.c b/cpus.c
> index 740b8dc3f8..fae7344df5 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -50,6 +50,8 @@
>  #include "qapi-event.h"
>  #include "hw/nmi.h"
>  #include "sysemu/replay.h"
> +#include "exec/cputlb.h"
> +#include "trace-root.h"
>  
>  #ifdef CONFIG_LINUX
>  
> @@ -1252,6 +1254,10 @@ static int tcg_cpu_exec(CPUState *cpu)
>      int64_t ti;
>  #endif
>  
> +    trace_tlb_flush_stats(tlb_self_flush_count,
> +                          tlb_async_flush_count,
> +                          tlb_synced_flush_count);
> +
>  #ifdef CONFIG_PROFILER
>      ti = profile_getclock();
>  #endif
> diff --git a/trace-events b/trace-events
> index b07a09ba95..fc23e15d25 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -94,6 +94,9 @@ disable exec_tb(void *tb, uintptr_t pc) "tb:%p 
> pc=0x%"PRIxPTR
>  disable exec_tb_nocache(void *tb, uintptr_t pc) "tb:%p pc=0x%"PRIxPTR
>  disable exec_tb_exit(void *last_tb, unsigned int flags) "tb:%p flags=%x"
>  
> +# cpus.c
> +tlb_flush_stats(int self, int async, int synced) "self:%d async:%d synced:%d"
> +
>  # translate-all.c
>  translate_block(void *tb, uintptr_t pc, uint8_t *tb_code) "tb:%p, 
> pc:0x%"PRIxPTR", tb_code:%p"
>  
>