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[Qemu-trivial] [PULL 21/24] exec: avoid unnecessary cacheline bounce on
From: |
Michael Tokarev |
Subject: |
[Qemu-trivial] [PULL 21/24] exec: avoid unnecessary cacheline bounce on ram_list.mru_block |
Date: |
Fri, 6 Nov 2015 15:43:58 +0300 |
From: Paolo Bonzini <address@hidden>
Whenever the MRU cache hits for the list of RAM blocks, qemu_get_ram_block
does an unnecessary write that causes a processor cache line to bounce
from one core to another. This causes a performance hit.
Reported-by: Emilio G. Cota <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Michael Tokarev <address@hidden>
---
exec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index ed88e72..a028961 100644
--- a/exec.c
+++ b/exec.c
@@ -903,7 +903,7 @@ static RAMBlock *qemu_get_ram_block(ram_addr_t addr)
block = atomic_rcu_read(&ram_list.mru_block);
if (block && addr - block->offset < block->max_length) {
- goto found;
+ return block;
}
QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
if (addr - block->offset < block->max_length) {
--
2.1.4
- Re: [Qemu-trivial] [PULL 17/24] qom/object: fix 2 comment typos, (continued)
[Qemu-trivial] [PULL 11/24] hw/dma/pxa2xx: Remove superfluous memset, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 16/24] configure: remove help string for 'vnc-tls' option, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 02/24] gdbstub: Fix buffer overflows in gdb_handle_packet(), Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 14/24] qxl: Use g_new() & friends where that makes obvious sense, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 19/24] ivshmem-server: fix possible OVERRUN, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 13/24] ui: Use g_new() & friends where that makes obvious sense, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 03/24] hw/display/tcx: Remove superfluous OBJECT() typecasts, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 24/24] tap-bsd: use user-specified tap device if it already exists, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 21/24] exec: avoid unnecessary cacheline bounce on ram_list.mru_block,
Michael Tokarev <=
[Qemu-trivial] [PULL 18/24] pci-assign: do not test path with access() before opening, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 07/24] xen: fix invalid assertion, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 05/24] fix bad indentation in pcie_cap_slot_write_config(), Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 22/24] taget-ppc: Fix read access to IBAT registers higher than IBAT3, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 12/24] bt: fix use of uninitialized variable seqlen, Michael Tokarev, 2015/11/06
Re: [Qemu-trivial] [Qemu-devel] [PULL 00/24] Trivial patches for 2015-11-06, Peter Maydell, 2015/11/06
[Qemu-trivial] [PULL 15/24] usb: Use g_new() & friends where that makes obvious sense, Michael Tokarev, 2015/11/06
[Qemu-trivial] [PULL 04/24] maint: Ignore ivshmem binaries, Michael Tokarev, 2015/11/06