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authorDavid S. Miller <davem@davemloft.net>2005-05-20 11:40:32 -0700
committerDavid S. Miller <davem@davemloft.net>2005-05-20 11:40:32 -0700
commita228dfd5dc4b92288ea22d427b2bfc48ba5bb8b0 (patch)
treebd3c9a5892a5e3823427c9d614fd6c9aee96c1fb
parent37e0915b701281182cea9fc90e894d10addf134a (diff)
[SPARC64]: Fix bad performance side effect of strbuf timeout changes.
The recent change to add a timeout to strbuf flushing had a negative performance impact. The udelay()'s are too long, and they were done in the wrong order wrt. the register read checks. Fix both, and things are happy again. There are more possible improvements in this area. In fact, PCI streaming buffer flushing seems to be part of the bottleneck in network receive performance on my SunBlade1000 box. Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc64/kernel/pci_iommu.c16
-rw-r--r--arch/sparc64/kernel/sbus.c4
2 files changed, 11 insertions, 9 deletions
diff --git a/arch/sparc64/kernel/pci_iommu.c b/arch/sparc64/kernel/pci_iommu.c
index f009b1b4550..33ca56c90da 100644
--- a/arch/sparc64/kernel/pci_iommu.c
+++ b/arch/sparc64/kernel/pci_iommu.c
@@ -392,14 +392,16 @@ static void pci_strbuf_flush(struct pci_strbuf *strbuf, struct pci_iommu *iommu,
flushreg = strbuf->strbuf_ctxflush;
matchreg = PCI_STC_CTXMATCH_ADDR(strbuf, ctx);
- limit = 10000;
- do {
- pci_iommu_write(flushreg, ctx);
- udelay(10);
+ limit = 100000;
+ pci_iommu_write(flushreg, ctx);
+ for(;;) {
+ if (((long)pci_iommu_read(matchreg)) >= 0L)
+ break;
limit--;
if (!limit)
break;
- } while(((long)pci_iommu_read(matchreg)) < 0L);
+ udelay(1);
+ }
if (!limit)
printk(KERN_WARNING "pci_strbuf_flush: ctx flush "
"timeout vaddr[%08x] ctx[%lx]\n",
@@ -414,12 +416,12 @@ static void pci_strbuf_flush(struct pci_strbuf *strbuf, struct pci_iommu *iommu,
pci_iommu_write(strbuf->strbuf_fsync, strbuf->strbuf_flushflag_pa);
(void) pci_iommu_read(iommu->write_complete_reg);
- limit = 10000;
+ limit = 100000;
while (!PCI_STC_FLUSHFLAG_SET(strbuf)) {
limit--;
if (!limit)
break;
- udelay(10);
+ udelay(1);
membar("#LoadLoad");
}
if (!limit)
diff --git a/arch/sparc64/kernel/sbus.c b/arch/sparc64/kernel/sbus.c
index d3eca98e1fe..76ea6455433 100644
--- a/arch/sparc64/kernel/sbus.c
+++ b/arch/sparc64/kernel/sbus.c
@@ -133,12 +133,12 @@ static void sbus_strbuf_flush(struct sbus_iommu *iommu, u32 base, unsigned long
iommu->strbuf_regs + STRBUF_FSYNC);
upa_readq(iommu->sbus_control_reg);
- limit = 10000;
+ limit = 100000;
while (iommu->strbuf_flushflag == 0UL) {
limit--;
if (!limit)
break;
- udelay(10);
+ udelay(1);
membar("#LoadLoad");
}
if (!limit)