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[Qemu-devel] [PATCH 19/31] Revert "openpic: Accelerate pending irq searc
From: |
Alexander Graf |
Subject: |
[Qemu-devel] [PATCH 19/31] Revert "openpic: Accelerate pending irq search" |
Date: |
Mon, 7 Jan 2013 16:38:48 +0100 |
From: Scott Wood <address@hidden>
This reverts commit a9bd83f4c65de0058659ede009fa1a241f379edd.
This counting approach is not robust against setting a bit that
was already set, or clearing a bit that was already clear. Perhaps
that is considered a bug, but besides the lack of any documentation
for that restriction, it's a pretty unpleasant way for the problem
to manifest itself.
It could be made more robust by testing the current value of the
bit before changing the count, but a later patch speeds up IRQ_check
in all cases, not just when there's nothing pending. Hopefully that
should be adequate to address performance concerns.
Signed-off-by: Scott Wood <address@hidden>
Signed-off-by: Alexander Graf <address@hidden>
---
hw/openpic.c | 11 -----------
1 files changed, 0 insertions(+), 11 deletions(-)
diff --git a/hw/openpic.c b/hw/openpic.c
index 19e6280..2c238fb 100644
--- a/hw/openpic.c
+++ b/hw/openpic.c
@@ -183,7 +183,6 @@ typedef struct IRQQueue {
uint32_t queue[BF_WIDTH(MAX_IRQ)];
int next;
int priority;
- int pending; /* nr of pending bits in queue */
} IRQQueue;
typedef struct IRQSource {
@@ -269,13 +268,11 @@ typedef struct OpenPICState {
static inline void IRQ_setbit(IRQQueue *q, int n_IRQ)
{
- q->pending++;
set_bit(q->queue, n_IRQ);
}
static inline void IRQ_resetbit(IRQQueue *q, int n_IRQ)
{
- q->pending--;
reset_bit(q->queue, n_IRQ);
}
@@ -291,12 +288,6 @@ static void IRQ_check(OpenPICState *opp, IRQQueue *q)
next = -1;
priority = -1;
-
- if (!q->pending) {
- /* IRQ bitmap is empty */
- goto out;
- }
-
for (i = 0; i < opp->max_irq; i++) {
if (IRQ_testbit(q, i)) {
DPRINTF("IRQ_check: irq %d set ivpr_pr=%d pr=%d\n",
@@ -307,8 +298,6 @@ static void IRQ_check(OpenPICState *opp, IRQQueue *q)
}
}
}
-
-out:
q->next = next;
q->priority = priority;
}
--
1.6.0.2
- [Qemu-devel] [PATCH 26/31] kvm: Update kernel headers, (continued)
- [Qemu-devel] [PATCH 26/31] kvm: Update kernel headers, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 28/31] PPC: Bring EPR support closer to reality, Alexander Graf, 2013/01/07
- Re: [Qemu-devel] [PULL 00/31] ppc patch queue 2013-01-07, Andreas Färber, 2013/01/07
- [Qemu-devel] [PATCH 21/31] openpic: add some bounds checking for IRQ numbers, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 23/31] openpic: IRQ_check: search the queue a word at a time, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 22/31] openpic: fix sense and priority bits, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 29/31] target-ppc: Slim conversion of model definitions to QOM subclasses, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 24/31] openpic: move IACK to its own function, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 25/31] openpic: fix CTPR and de-assertion of interrupts, Alexander Graf, 2013/01/07
- [Qemu-devel] [PATCH 19/31] Revert "openpic: Accelerate pending irq search",
Alexander Graf <=