| Message ID | 1397767775-10965-7-git-send-email-nm@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Thu, Apr 17, 2014 at 03:49:22PM -0500, Nishanth Menon wrote: > just simplify derefencing that is equivalent. > > Signed-off-by: Nishanth Menon <nm@ti.com> > --- > V2: just ordering change > V1: https://patchwork.kernel.org/patch/3984201/ > drivers/bus/omap_l3_noc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c > index c8facb0..f7d3bf4 100644 > --- a/drivers/bus/omap_l3_noc.c > +++ b/drivers/bus/omap_l3_noc.c > @@ -76,7 +76,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) > err_src = __ffs(err_reg); > > /* Read the stderrlog_main_source from clk domain */ > - l3_targ_base = base + *(l3_targ[i] + err_src); > + l3_targ_base = base + l3_targ[i][err_src]; hmmm, wasn't it so that pointer arithmetic was slightly faster than array indexing ? In that case would it be best to: l3_targ_base = base + *(l3_targ + i + err_src);
On 04/17/2014 05:00 PM, Felipe Balbi wrote: > On Thu, Apr 17, 2014 at 03:49:22PM -0500, Nishanth Menon wrote: >> just simplify derefencing that is equivalent. >> >> Signed-off-by: Nishanth Menon <nm@ti.com> >> --- >> V2: just ordering change >> V1: https://patchwork.kernel.org/patch/3984201/ >> drivers/bus/omap_l3_noc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c >> index c8facb0..f7d3bf4 100644 >> --- a/drivers/bus/omap_l3_noc.c >> +++ b/drivers/bus/omap_l3_noc.c >> @@ -76,7 +76,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) >> err_src = __ffs(err_reg); >> >> /* Read the stderrlog_main_source from clk domain */ >> - l3_targ_base = base + *(l3_targ[i] + err_src); >> + l3_targ_base = base + l3_targ[i][err_src]; > > hmmm, wasn't it so that pointer arithmetic was slightly faster than > array indexing ? In that case would it be best to: > > l3_targ_base = base + *(l3_targ + i + err_src); > Yes, if this was a hot path (example: interrupt handler that gets invoked very often), I would probably have preferred optimization at this point. However, the patch is just a step away from patches that converts the target information into a structure under flagmux structure allowing us to get rid of multiple array operations. This patch just makes the further changes a bit readable.
On Mon, Apr 21, 2014 at 08:08:43AM -0500, Nishanth Menon wrote: > On 04/17/2014 05:00 PM, Felipe Balbi wrote: > > On Thu, Apr 17, 2014 at 03:49:22PM -0500, Nishanth Menon wrote: > >> just simplify derefencing that is equivalent. > >> > >> Signed-off-by: Nishanth Menon <nm@ti.com> > >> --- > >> V2: just ordering change > >> V1: https://patchwork.kernel.org/patch/3984201/ > >> drivers/bus/omap_l3_noc.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c > >> index c8facb0..f7d3bf4 100644 > >> --- a/drivers/bus/omap_l3_noc.c > >> +++ b/drivers/bus/omap_l3_noc.c > >> @@ -76,7 +76,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) > >> err_src = __ffs(err_reg); > >> > >> /* Read the stderrlog_main_source from clk domain */ > >> - l3_targ_base = base + *(l3_targ[i] + err_src); > >> + l3_targ_base = base + l3_targ[i][err_src]; > > > > hmmm, wasn't it so that pointer arithmetic was slightly faster than > > array indexing ? In that case would it be best to: > > > > l3_targ_base = base + *(l3_targ + i + err_src); > > > Yes, if this was a hot path (example: interrupt handler that gets > invoked very often), I would probably have preferred optimization at > this point. > > However, the patch is just a step away from patches that converts the > target information into a structure under flagmux structure allowing > us to get rid of multiple array operations. > > This patch just makes the further changes a bit readable. alright, the error IRQ doesn't fire very often indeed.
diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c index c8facb0..f7d3bf4 100644 --- a/drivers/bus/omap_l3_noc.c +++ b/drivers/bus/omap_l3_noc.c @@ -76,7 +76,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) err_src = __ffs(err_reg); /* Read the stderrlog_main_source from clk domain */ - l3_targ_base = base + *(l3_targ[i] + err_src); + l3_targ_base = base + l3_targ[i][err_src]; l3_targ_stderr = l3_targ_base + L3_TARG_STDERRLOG_MAIN; l3_targ_slvofslsb = l3_targ_base + L3_TARG_STDERRLOG_SLVOFSLSB;
just simplify derefencing that is equivalent. Signed-off-by: Nishanth Menon <nm@ti.com> --- V2: just ordering change V1: https://patchwork.kernel.org/patch/3984201/ drivers/bus/omap_l3_noc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)