On May 16, 2014, at 2:43 PM, Andi Kleen <a...@firstfloor.org> wrote:
> From: Andi Kleen <a...@linux.intel.com>
>
> ixgbe_read_reg and ixgbe_write_reg are frequently called and are very big
> because they have complex error handling code.
Actually, this patch doesn't do anything to ixgbe_write_reg, which would almost
certainly be very bad for performance, but instead changes ixgbe_write_reg64.
The latter is not in a performance-sensitive path, but is only called from one
site, so there is little reason to take it out-of-line.
I already have a patch in queue to make ixgbe_read_reg out-of-line, because it
does have a very costly memory footprint inline, as you have found.
> Moving them out of line saves ~27k text in the ixgbe driver.
>
> text data bss dec hex filename
> 14220873 2008072 1507328 17736273 10ea251 vmlinux-before-ixgbe
> 14193673 2003976 1507328 17704977 10e2811 vmlinux-ixgbe
>
> Cc: net...@vger.kernel.org
> Cc: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
> Signed-off-by: Andi Kleen <a...@linux.intel.com>
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe_common.h | 22 ++--------------------
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 22 ++++++++++++++++++++++
> 2 files changed, 24 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> index f12c40f..05f094d 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
> @@ -162,28 +162,10 @@ static inline void writeq(u64 val, void __iomem *addr)
> }
> #endif
>
> -static inline void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value)
> -{
> - u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
> +void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value);
> +u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg);
>
> - if (ixgbe_removed(reg_addr))
> - return;
> - writeq(value, reg_addr + reg);
> -}
> #define IXGBE_WRITE_REG64(a, reg, value) ixgbe_write_reg64((a), (reg),
> (value))
> -
> -static inline u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg)
> -{
> - u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
> - u32 value;
> -
> - if (ixgbe_removed(reg_addr))
> - return IXGBE_FAILED_READ_REG;
> - value = readl(reg_addr + reg);
> - if (unlikely(value == IXGBE_FAILED_READ_REG))
> - ixgbe_check_remove(hw, reg);
> - return value;
> -}
> #define IXGBE_READ_REG(a, reg) ixgbe_read_reg((a), (reg))
>
> #define IXGBE_WRITE_REG_ARRAY(a, reg, offset, value) \
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index d62e7a2..5f81f62 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -371,6 +371,28 @@ void ixgbe_write_pci_cfg_word(struct ixgbe_hw *hw, u32
> reg, u16 value)
> pci_write_config_word(adapter->pdev, reg, value);
> }
>
> +void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value)
> +{
> + u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
> +
> + if (ixgbe_removed(reg_addr))
> + return;
> + writeq(value, reg_addr + reg);
> +}
> +
> +u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg)
> +{
> + u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
> + u32 value;
> +
> + if (ixgbe_removed(reg_addr))
> + return IXGBE_FAILED_READ_REG;
> + value = readl(reg_addr + reg);
> + if (unlikely(value == IXGBE_FAILED_READ_REG))
> + ixgbe_check_remove(hw, reg);
> + return value;
> +}
> +
> static void ixgbe_service_event_complete(struct ixgbe_adapter *adapter)
> {
> BUG_ON(!test_bit(__IXGBE_SERVICE_SCHED, &adapter->state));
> --
> 1.9.0
>
> --
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--
Mark Rustad, Networking Division, Intel Corporation
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