| Message ID | 201606242018.u5OKISiY007160@linux03a.ddci.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jun 24, 2016 at 01:18:28PM -0700, Aaron Larson wrote: > > Call gen_pause for all "or rx,rx,rx" encodings other nop. This > provides a reasonable implementation for yield, and a better > approximation for mdoio, mdoom, and miso. The choice to pause for all > encodings !=0 leverages the PowerISA admonition that the reserved > encodings might change program priority, providing a slight "future > proofing". > > Signed-off-by: Aaron Larson <alarson@ddci.com> As far as I can tell, this is ok. However, I'd like to get a second opinion from agraf or BenH before I apply it. > --- > target-ppc/translate.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/target-ppc/translate.c b/target-ppc/translate.c > index 2f1c591..c4559b6 100644 > --- a/target-ppc/translate.c > +++ b/target-ppc/translate.c > @@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx) > } else if (unlikely(Rc(ctx->opcode) != 0)) { > gen_set_Rc0(ctx, cpu_gpr[rs]); > #if defined(TARGET_PPC64) > - } else { > + } else if (rs != 0) { /* 0 is nop */ > int prio = 0; > > switch (rs) { > @@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx) > break; > #endif > default: > - /* nop */ > break; > } > if (prio) { > @@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx) > tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50); > gen_store_spr(SPR_PPR, t0); > tcg_temp_free(t0); > - /* Pause us out of TCG otherwise spin loops with smt_low > - * eat too much CPU and the kernel hangs > - */ > + } > #if !defined(CONFIG_USER_ONLY) > - gen_pause(ctx); > + /* Pause out of TCG otherwise spin loops with smt_low eat too much > + * CPU and the kernel hangs. This applies to all encodings other > + * than no-op, e.g., miso(rs=26), yield(27), mdoio(29), mdoom(30), > + * and all currently undefined. > + */ > + gen_pause(ctx); > #endif > - } > #endif > } > }
On Fri, 2016-06-24 at 13:18 -0700, Aaron Larson wrote: > Call gen_pause for all "or rx,rx,rx" encodings other nop. This > provides a reasonable implementation for yield, and a better > approximation for mdoio, mdoom, and miso. The choice to pause for > all > encodings !=0 leverages the PowerISA admonition that the reserved > encodings might change program priority, providing a slight "future > proofing". > > Signed-off-by: Aaron Larson <alarson@ddci.com> Acked-by: Benjamin Herrenschmidt <benh@kerne.crashing.org> > --- > target-ppc/translate.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/target-ppc/translate.c b/target-ppc/translate.c > index 2f1c591..c4559b6 100644 > --- a/target-ppc/translate.c > +++ b/target-ppc/translate.c > @@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx) > } else if (unlikely(Rc(ctx->opcode) != 0)) { > gen_set_Rc0(ctx, cpu_gpr[rs]); > #if defined(TARGET_PPC64) > - } else { > + } else if (rs != 0) { /* 0 is nop */ > int prio = 0; > > switch (rs) { > @@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx) > break; > #endif > default: > - /* nop */ > break; > } > if (prio) { > @@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx) > tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50); > gen_store_spr(SPR_PPR, t0); > tcg_temp_free(t0); > - /* Pause us out of TCG otherwise spin loops with smt_low > - * eat too much CPU and the kernel hangs > - */ > + } > #if !defined(CONFIG_USER_ONLY) > - gen_pause(ctx); > + /* Pause out of TCG otherwise spin loops with smt_low eat > too much > + * CPU and the kernel hangs. This applies to all encodings > other > + * than no-op, e.g., miso(rs=26), yield(27), mdoio(29), > mdoom(30), > + * and all currently undefined. > + */ > + gen_pause(ctx); > #endif > - } > #endif > } > }
On Wed, Jun 29, 2016 at 10:00:57PM +1000, Benjamin Herrenschmidt wrote: > On Fri, 2016-06-24 at 13:18 -0700, Aaron Larson wrote: > > Call gen_pause for all "or rx,rx,rx" encodings other nop. This > > provides a reasonable implementation for yield, and a better > > approximation for mdoio, mdoom, and miso. The choice to pause for > > all > > encodings !=0 leverages the PowerISA admonition that the reserved > > encodings might change program priority, providing a slight "future > > proofing". > > > > Signed-off-by: Aaron Larson <alarson@ddci.com> > > Acked-by: Benjamin Herrenschmidt <benh@kerne.crashing.org> Applied to ppc-for-2.7, thanks. > > --- > > target-ppc/translate.c | 15 ++++++++------- > > 1 file changed, 8 insertions(+), 7 deletions(-) > > > > diff --git a/target-ppc/translate.c b/target-ppc/translate.c > > index 2f1c591..c4559b6 100644 > > --- a/target-ppc/translate.c > > +++ b/target-ppc/translate.c > > @@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx) > > } else if (unlikely(Rc(ctx->opcode) != 0)) { > > gen_set_Rc0(ctx, cpu_gpr[rs]); > > #if defined(TARGET_PPC64) > > - } else { > > + } else if (rs != 0) { /* 0 is nop */ > > int prio = 0; > > > > switch (rs) { > > @@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx) > > break; > > #endif > > default: > > - /* nop */ > > break; > > } > > if (prio) { > > @@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx) > > tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50); > > gen_store_spr(SPR_PPR, t0); > > tcg_temp_free(t0); > > - /* Pause us out of TCG otherwise spin loops with smt_low > > - * eat too much CPU and the kernel hangs > > - */ > > + } > > #if !defined(CONFIG_USER_ONLY) > > - gen_pause(ctx); > > + /* Pause out of TCG otherwise spin loops with smt_low eat > > too much > > + * CPU and the kernel hangs. This applies to all encodings > > other > > + * than no-op, e.g., miso(rs=26), yield(27), mdoio(29), > > mdoom(30), > > + * and all currently undefined. > > + */ > > + gen_pause(ctx); > > #endif > > - } > > #endif > > } > > } >
diff --git a/target-ppc/translate.c b/target-ppc/translate.c index 2f1c591..c4559b6 100644 --- a/target-ppc/translate.c +++ b/target-ppc/translate.c @@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx) } else if (unlikely(Rc(ctx->opcode) != 0)) { gen_set_Rc0(ctx, cpu_gpr[rs]); #if defined(TARGET_PPC64) - } else { + } else if (rs != 0) { /* 0 is nop */ int prio = 0; switch (rs) { @@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx) break; #endif default: - /* nop */ break; } if (prio) { @@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx) tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50); gen_store_spr(SPR_PPR, t0); tcg_temp_free(t0); - /* Pause us out of TCG otherwise spin loops with smt_low - * eat too much CPU and the kernel hangs - */ + } #if !defined(CONFIG_USER_ONLY) - gen_pause(ctx); + /* Pause out of TCG otherwise spin loops with smt_low eat too much + * CPU and the kernel hangs. This applies to all encodings other + * than no-op, e.g., miso(rs=26), yield(27), mdoio(29), mdoom(30), + * and all currently undefined. + */ + gen_pause(ctx); #endif - } #endif } }
Call gen_pause for all "or rx,rx,rx" encodings other nop. This provides a reasonable implementation for yield, and a better approximation for mdoio, mdoom, and miso. The choice to pause for all encodings !=0 leverages the PowerISA admonition that the reserved encodings might change program priority, providing a slight "future proofing". Signed-off-by: Aaron Larson <alarson@ddci.com> --- target-ppc/translate.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)