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ath9k_hw: optimize all descriptor access functions

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Because all of the descriptor data structures are marked as __packed, GCC
assumes the worst case wrt. alignment and generates unaligned load/store
instructions on MIPS for access to all fields.
Since descriptors always have to be 4-byte-aligned, we can just mark the
data structures with __aligned(4), which allows GCC to generate much more
efficient code.
Verified through disassembly and OProfile comparisons.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Felix Fietkau 2010-10-16 01:01:48 +02:00 committed by John W. Linville
parent f0e94b479c
commit ada9f1cacb
2 changed files with 5 additions and 5 deletions
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6
drivers/net/wireless/ath/ath9k/ar9003_mac.h
View File

@ -65,7 +65,7 @@ struct ar9003_rxs {
u32 status9;
u32 status10;
u32 status11;
} __packed;
} __packed __aligned(4);
/* Transmit Control Descriptor */
struct ar9003_txc {
@ -93,7 +93,7 @@ struct ar9003_txc {
u32 ctl21; /* DMA control 21 */
u32 ctl22; /* DMA control 22 */
u32 pad[9]; /* pad to cache line (128 bytes/32 dwords) */
} __packed;
} __packed __aligned(4);
struct ar9003_txs {
u32 ds_info;
@ -105,7 +105,7 @@ struct ar9003_txs {
u32 status6;
u32 status7;
u32 status8;
} __packed;
} __packed __aligned(4);
void ar9003_hw_attach_mac_ops(struct ath_hw *hw);
void ath9k_hw_set_rx_bufsize(struct ath_hw *ah, u16 buf_size);

4
drivers/net/wireless/ath/ath9k/mac.h
View File

@ -237,7 +237,7 @@ struct ath_desc {
u32 ds_ctl1;
u32 ds_hw[20];
void *ds_vdata;
} __packed;
} __packed __aligned(4);
#define ATH9K_TXDESC_CLRDMASK 0x0001
#define ATH9K_TXDESC_NOACK 0x0002
@ -307,7 +307,7 @@ struct ar5416_desc {
u32 status8;
} rx;
} u;
} __packed;
} __packed __aligned(4);
#define AR5416DESC(_ds) ((struct ar5416_desc *)(_ds))
#define AR5416DESC_CONST(_ds) ((const struct ar5416_desc *)(_ds))