unicorn/qemu/include
Emilio G. Cota ab569f5cde
atomics: do not emit consume barrier for atomic_rcu_read
Currently we emit a consume-load in atomic_rcu_read. Because of
limitations in current compilers, this is overkill for non-Alpha hosts
and it is only useful to make Thread Sanitizer work.

This patch leaves the consume-load in atomic_rcu_read when
compiling with Thread Sanitizer enabled, and resorts to a
relaxed load + smp_read_barrier_depends otherwise.

On an RMO host architecture, such as aarch64, the performance
improvement of this change is easily measurable. For instance,
qht-bench performs an atomic_rcu_read on every lookup. Performance
before and after applying this patch:

$ tests/qht-bench -d 5 -n 1
Before: 9.78 MT/s
After: 10.96 MT/s

Backports commit 15487aa132109891482f79d78a30d6cfd465a391 from qemu
2018-02-24 03:28:11 -05:00
..
crypto Drop unused crypto source files 2018-02-17 15:23:57 -05:00
exec memory: Remove code for mr->may_overlap 2018-02-24 02:55:25 -05:00
fpu fpu: Remove use of int_fast16_t in conversions to int16 2018-02-20 16:54:04 -05:00
hw hw: clean up hw/hw.h includes 2018-02-24 02:46:41 -05:00
qapi qapi: Change visit_type_FOO() to no longer return partial objects 2018-02-23 19:53:17 -05:00
qemu atomics: do not emit consume barrier for atomic_rcu_read 2018-02-24 03:28:11 -05:00
qom cpu: move exec-all.h inclusion out of cpu.h 2018-02-24 02:39:08 -05:00
sysemu accel: make configure_accelerator return void 2018-02-24 00:31:28 -05:00
config.h
elf.h fix merge conflicts 2017-03-10 21:04:33 +08:00
glib_compat.h glib_compat: backport hashtable iterator interfaces 2018-02-21 13:18:44 -05:00
qemu-common.h qemu-common: push cpu.h inclusion out of qemu-common.h 2018-02-24 01:50:56 -05:00