aboutsummaryrefslogtreecommitdiffstats
path: root/drivers
diff options
context:
space:
mode:
authorAndreas Mohr <andi@rhlx01.fht-esslingen.de>2005-04-11 19:47:43 -0400
committerJeff Garzik <jgarzik@pobox.com>2005-06-26 18:24:00 -0400
commit93ad4fb04f5dd82fe8ace1db7617c9dcb954cf60 (patch)
treeea30ca1f10063901325083e4ec059b576ae31186 /drivers
parent1e7f0bd8c8f2d0496ad338be5e69ff4395d77da4 (diff)
[PATCH] pcnet_cs.c: IRQ handler optimization
During some performance diagnostics I stumbled on this slightly wasteful code in pcnet_cs.c which I made the patch included at the bottom for (two minor comment fixes included). Improvement: instead of *always* calculating lea 0x2c0(%edx),%ebx and then additionally doing the mov %edx,0xc0(%ebx) addition *if we need it*, we now do the *whole* calculation of mov %edx,0x380(%ebx) *only* if we need it. This even manages to save us a whole 16-byte alignment buffer loss in this compilation case. Result: slightly improves IRQ handler performance in both shared and non-shared IRQ case, which should make my rusty P3/700 a slight bit happier. Thank you for your support, Andreas Mohr old asm result (using gcc 3.3.5): 000015a0 <ei_irq_wrapper>: 15a0: 55 push %ebp 15a1: 89 e5 mov %esp,%ebp 15a3: 53 push %ebx 15a4: 8d 9a c0 02 00 00 lea 0x2c0(%edx),%ebx 15aa: e8 fc ff ff ff call 15ab <ei_irq_wrapper+0xb> 15af: 83 f8 01 cmp $0x1,%eax 15b2: 74 03 je 15b7 <ei_irq_wrapper+0x17> 15b4: 5b pop %ebx 15b5: 5d pop %ebp 15b6: c3 ret 15b7: 31 d2 xor %edx,%edx 15b9: 89 93 c0 00 00 00 mov %edx,0xc0(%ebx) 15bf: eb f3 jmp 15b4 <ei_irq_wrapper+0x14> 15c1: eb 0d jmp 15d0 <ei_watchdog> 15c3: 90 nop 15c4: 90 nop 15c5: 90 nop 15c6: 90 nop 15c7: 90 nop 15c8: 90 nop 15c9: 90 nop 15ca: 90 nop 15cb: 90 nop 15cc: 90 nop 15cd: 90 nop 15ce: 90 nop 15cf: 90 nop 000015d0 <ei_watchdog>: new asm result: 000015a0 <ei_irq_wrapper>: 15a0: 55 push %ebp 15a1: 89 e5 mov %esp,%ebp 15a3: 53 push %ebx 15a4: 89 d3 mov %edx,%ebx 15a6: e8 fc ff ff ff call 15a7 <ei_irq_wrapper+0x7> 15ab: 83 f8 01 cmp $0x1,%eax 15ae: 74 03 je 15b3 <ei_irq_wrapper+0x13> 15b0: 5b pop %ebx 15b1: 5d pop %ebp 15b2: c3 ret 15b3: 31 d2 xor %edx,%edx 15b5: 89 93 80 03 00 00 mov %edx,0x380(%ebx) 15bb: eb f3 jmp 15b0 <ei_irq_wrapper+0x10> 15bd: 8d 76 00 lea 0x0(%esi),%esi 000015c0 <ei_watchdog>: Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/pcmcia/pcnet_cs.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/net/pcmcia/pcnet_cs.c b/drivers/net/pcmcia/pcnet_cs.c
index 181b6ed55003..f3ea4a9f2bf1 100644
--- a/drivers/net/pcmcia/pcnet_cs.c
+++ b/drivers/net/pcmcia/pcnet_cs.c
@@ -1155,11 +1155,13 @@ static int set_config(struct net_device *dev, struct ifmap *map)
1155static irqreturn_t ei_irq_wrapper(int irq, void *dev_id, struct pt_regs *regs) 1155static irqreturn_t ei_irq_wrapper(int irq, void *dev_id, struct pt_regs *regs)
1156{ 1156{
1157 struct net_device *dev = dev_id; 1157 struct net_device *dev = dev_id;
1158 pcnet_dev_t *info = PRIV(dev); 1158 pcnet_dev_t *info;
1159 irqreturn_t ret = ei_interrupt(irq, dev_id, regs); 1159 irqreturn_t ret = ei_interrupt(irq, dev_id, regs);
1160 1160
1161 if (ret == IRQ_HANDLED) 1161 if (ret == IRQ_HANDLED) {
1162 info = PRIV(dev);
1162 info->stale = 0; 1163 info->stale = 0;
1164 }
1163 return ret; 1165 return ret;
1164} 1166}
1165 1167
@@ -1350,7 +1352,7 @@ static void dma_block_input(struct net_device *dev, int count,
1350 if (count & 0x01) 1352 if (count & 0x01)
1351 buf[count-1] = inb(nic_base + PCNET_DATAPORT), xfer_count++; 1353 buf[count-1] = inb(nic_base + PCNET_DATAPORT), xfer_count++;
1352 1354
1353 /* This was for the ALPHA version only, but enough people have 1355 /* This was for the ALPHA version only, but enough people have been
1354 encountering problems that it is still here. */ 1356 encountering problems that it is still here. */
1355#ifdef PCMCIA_DEBUG 1357#ifdef PCMCIA_DEBUG
1356 if (ei_debug > 4) { /* DMA termination address check... */ 1358 if (ei_debug > 4) { /* DMA termination address check... */
@@ -1424,7 +1426,7 @@ static void dma_block_output(struct net_device *dev, int count,
1424 dma_start = jiffies; 1426 dma_start = jiffies;
1425 1427
1426#ifdef PCMCIA_DEBUG 1428#ifdef PCMCIA_DEBUG
1427 /* This was for the ALPHA version only, but enough people have 1429 /* This was for the ALPHA version only, but enough people have been
1428 encountering problems that it is still here. */ 1430 encountering problems that it is still here. */
1429 if (ei_debug > 4) { /* DMA termination address check... */ 1431 if (ei_debug > 4) { /* DMA termination address check... */
1430 int addr, tries = 20; 1432 int addr, tries = 20;