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[Qemu-devel] [PATCH] apic: Don't iterate past last used apic
From: |
Alex Williamson |
Subject: |
[Qemu-devel] [PATCH] apic: Don't iterate past last used apic |
Date: |
Tue, 14 Sep 2010 09:13:13 -0600 |
User-agent: |
StGIT/0.14.3 |
local_apics are allocated sequentially and never removed, so
we can stop any iterations that go to MAX_APICS as soon as we
hit the first NULL. Looking at a small guest running a virtio-net
workload with oprofile, this drops apic_get_delivery_bitmask()
from #3 in the profile to down in the noise.
Signed-off-by: Alex Williamson <address@hidden>
---
Post 0.13
hw/apic.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/hw/apic.c b/hw/apic.c
index d686b51..c07238c 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -449,6 +449,8 @@ static int apic_find_dest(uint8_t dest)
apic = local_apics[i];
if (apic && apic->id == dest)
return i;
+ if (!apic)
+ break;
}
return -1;
@@ -484,6 +486,8 @@ static void apic_get_delivery_bitmask(uint32_t
*deliver_bitmask,
set_bit(deliver_bitmask, i);
}
}
+ } else {
+ break;
}
}
}
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