| Message ID | 20190614171200.21078-2-alex.bennee@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tcg plugin support | expand |
On 6/14/19 10:11 AM, Alex Bennée wrote: > From: "Emilio G. Cota" <cota@braap.org> > > This will allow us to trace 16B-long memory accesses. > > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > Signed-off-by: Emilio G. Cota <cota@braap.org> > --- > trace-events | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/trace-events b/trace-events > index 844ee58dd9..037169aab3 100644 > --- a/trace-events > +++ b/trace-events > @@ -159,7 +159,7 @@ vcpu guest_cpu_reset(void) > # Access information can be parsed as: > # > # struct mem_info { > -# uint8_t size_shift : 2; /* interpreted as "1 << size_shift" bytes */ > +# uint8_t size_shift : 3; /* interpreted as "1 << size_shift" bytes */ > # bool sign_extend: 1; /* sign-extended */ > # uint8_t endianness : 1; /* 0: little, 1: big */ > # bool store : 1; /* wheter it's a store operation */ > Well, 128B-long memory accesses. But SVE supports 256B memory accesses already. So why not add one more bit now. r~
Richard Henderson <richard.henderson@linaro.org> writes: > On 6/14/19 10:11 AM, Alex Bennée wrote: >> From: "Emilio G. Cota" <cota@braap.org> >> >> This will allow us to trace 16B-long memory accesses. >> >> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> >> Signed-off-by: Emilio G. Cota <cota@braap.org> >> --- >> trace-events | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/trace-events b/trace-events >> index 844ee58dd9..037169aab3 100644 >> --- a/trace-events >> +++ b/trace-events >> @@ -159,7 +159,7 @@ vcpu guest_cpu_reset(void) >> # Access information can be parsed as: >> # >> # struct mem_info { >> -# uint8_t size_shift : 2; /* interpreted as "1 << size_shift" bytes */ >> +# uint8_t size_shift : 3; /* interpreted as "1 << size_shift" bytes */ >> # bool sign_extend: 1; /* sign-extended */ >> # uint8_t endianness : 1; /* 0: little, 1: big */ >> # bool store : 1; /* wheter it's a store operation */ >> > > Well, 128B-long memory accesses. But SVE supports 256B memory accesses > already. So why not add one more bit now. Good point. Do we have any architectures that do load/stores that are not power of 2? I guess the SVE non-faulting accesses are treated as a series of elem size accesses. > > > r~ -- Alex Bennée
On 6/17/19 1:22 AM, Alex Bennée wrote: > > Richard Henderson <richard.henderson@linaro.org> writes: > >> On 6/14/19 10:11 AM, Alex Bennée wrote: >>> From: "Emilio G. Cota" <cota@braap.org> >>> >>> This will allow us to trace 16B-long memory accesses. >>> >>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> >>> Signed-off-by: Emilio G. Cota <cota@braap.org> >>> --- >>> trace-events | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/trace-events b/trace-events >>> index 844ee58dd9..037169aab3 100644 >>> --- a/trace-events >>> +++ b/trace-events >>> @@ -159,7 +159,7 @@ vcpu guest_cpu_reset(void) >>> # Access information can be parsed as: >>> # >>> # struct mem_info { >>> -# uint8_t size_shift : 2; /* interpreted as "1 << size_shift" bytes */ >>> +# uint8_t size_shift : 3; /* interpreted as "1 << size_shift" bytes */ >>> # bool sign_extend: 1; /* sign-extended */ >>> # uint8_t endianness : 1; /* 0: little, 1: big */ >>> # bool store : 1; /* wheter it's a store operation */ >>> >> >> Well, 128B-long memory accesses. But SVE supports 256B memory accesses >> already. So why not add one more bit now. > > Good point. > > Do we have any architectures that do load/stores that are not power of > 2? I guess the SVE non-faulting accesses are treated as a series of elem > size accesses. Yes, non-faults are in addition predicated, so each element is considered individually. Even the SVE non-predicated load/stores can technically be considered a sequence of byte operations. Which, I suppose could be helpful, because SVE can otherwise be configured to do non-power-of-2 operations. r~
diff --git a/trace-events b/trace-events index 844ee58dd9..037169aab3 100644 --- a/trace-events +++ b/trace-events @@ -159,7 +159,7 @@ vcpu guest_cpu_reset(void) # Access information can be parsed as: # # struct mem_info { -# uint8_t size_shift : 2; /* interpreted as "1 << size_shift" bytes */ +# uint8_t size_shift : 3; /* interpreted as "1 << size_shift" bytes */ # bool sign_extend: 1; /* sign-extended */ # uint8_t endianness : 1; /* 0: little, 1: big */ # bool store : 1; /* wheter it's a store operation */