| Message ID | 20231009124859.3373696-2-rjones@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] target/riscv: Use env_archcpu for better performance | expand |
On 9/10/23 14:48, Richard W.M. Jones wrote: > RISCV_CPU(cs) uses a checked cast. When QOM cast debugging is enabled > this adds about 5% total overhead when emulating RV64 on x86-64 host. > > Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk > disk. The guest has a copy of the qemu source tree. The test > involves compiling the qemu source tree with 'make clean; time make -j16'. > > Before making this change the compile step took 449 & 447 seconds over > two consecutive runs. > > After making this change: 428 & 421 seconds. > > The saving is over 5%. > > Thanks: Paolo Bonzini > Thanks: Philippe Mathieu-Daudé > Signed-off-by: Richard W.M. Jones <rjones@redhat.com> > --- > target/riscv/cpu_helper.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
On 10/9/23 05:48, Richard W.M. Jones wrote: > RISCV_CPU(cs) uses a checked cast. When QOM cast debugging is enabled > this adds about 5% total overhead when emulating RV64 on x86-64 host. > > Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk > disk. The guest has a copy of the qemu source tree. The test > involves compiling the qemu source tree with 'make clean; time make -j16'. > > Before making this change the compile step took 449 & 447 seconds over > two consecutive runs. > > After making this change: 428 & 421 seconds. > > The saving is over 5%. > > Thanks: Paolo Bonzini > Thanks: Philippe Mathieu-Daudé > Signed-off-by: Richard W.M. Jones <rjones@redhat.com> > --- > target/riscv/cpu_helper.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On Mon, Oct 9, 2023 at 10:50 PM Richard W.M. Jones <rjones@redhat.com> wrote: > > RISCV_CPU(cs) uses a checked cast. When QOM cast debugging is enabled > this adds about 5% total overhead when emulating RV64 on x86-64 host. > > Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk > disk. The guest has a copy of the qemu source tree. The test > involves compiling the qemu source tree with 'make clean; time make -j16'. > > Before making this change the compile step took 449 & 447 seconds over > two consecutive runs. > > After making this change: 428 & 421 seconds. > > The saving is over 5%. > > Thanks: Paolo Bonzini > Thanks: Philippe Mathieu-Daudé > Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Alistair > --- > target/riscv/cpu_helper.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c > index 3a02079290..8c28241c18 100644 > --- a/target/riscv/cpu_helper.c > +++ b/target/riscv/cpu_helper.c > @@ -65,8 +65,7 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch) > void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc, > uint64_t *cs_base, uint32_t *pflags) > { > - CPUState *cs = env_cpu(env); > - RISCVCPU *cpu = RISCV_CPU(cs); > + RISCVCPU *cpu = env_archcpu(env); > RISCVExtStatus fs, vs; > uint32_t flags = 0; > > -- > 2.41.0 > >
On Mon, Oct 9, 2023 at 10:50 PM Richard W.M. Jones <rjones@redhat.com> wrote: > > RISCV_CPU(cs) uses a checked cast. When QOM cast debugging is enabled > this adds about 5% total overhead when emulating RV64 on x86-64 host. > > Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk > disk. The guest has a copy of the qemu source tree. The test > involves compiling the qemu source tree with 'make clean; time make -j16'. > > Before making this change the compile step took 449 & 447 seconds over > two consecutive runs. > > After making this change: 428 & 421 seconds. > > The saving is over 5%. > > Thanks: Paolo Bonzini > Thanks: Philippe Mathieu-Daudé > Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Thanks! Applied to riscv-to-apply.next Alistair > --- > target/riscv/cpu_helper.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c > index 3a02079290..8c28241c18 100644 > --- a/target/riscv/cpu_helper.c > +++ b/target/riscv/cpu_helper.c > @@ -65,8 +65,7 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch) > void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc, > uint64_t *cs_base, uint32_t *pflags) > { > - CPUState *cs = env_cpu(env); > - RISCVCPU *cpu = RISCV_CPU(cs); > + RISCVCPU *cpu = env_archcpu(env); > RISCVExtStatus fs, vs; > uint32_t flags = 0; > > -- > 2.41.0 > >
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 3a02079290..8c28241c18 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -65,8 +65,7 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch) void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc, uint64_t *cs_base, uint32_t *pflags) { - CPUState *cs = env_cpu(env); - RISCVCPU *cpu = RISCV_CPU(cs); + RISCVCPU *cpu = env_archcpu(env); RISCVExtStatus fs, vs; uint32_t flags = 0;
RISCV_CPU(cs) uses a checked cast. When QOM cast debugging is enabled this adds about 5% total overhead when emulating RV64 on x86-64 host. Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk disk. The guest has a copy of the qemu source tree. The test involves compiling the qemu source tree with 'make clean; time make -j16'. Before making this change the compile step took 449 & 447 seconds over two consecutive runs. After making this change: 428 & 421 seconds. The saving is over 5%. Thanks: Paolo Bonzini Thanks: Philippe Mathieu-Daudé Signed-off-by: Richard W.M. Jones <rjones@redhat.com> --- target/riscv/cpu_helper.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)