d0aaf08bb9
Now we no longer have dynamic state affecting things we can remove the
additional fields in cpu.h and simplify the TB hash calculation.
For the benchmark:
hyperfine -w 2 -m 20 \
"./arm-softmmu/qemu-system-arm -cpu cortex-a15 \
-machine type=virt,highmem=off \
-display none -m 2048 \
-serial mon:stdio \
-netdev user,id=unet,hostfwd=tcp::2222-:22 \
-device virtio-net-pci,netdev=unet \
-device virtio-scsi-pci \
-blockdev driver=raw,node-name=hd,discard=unmap,file.driver=host_device,file.filename=/dev/zen-disk/debian-bullseye-armhf \
-device scsi-hd,drive=hd -smp 4 \
-kernel /home/alex/lsrc/linux.git/builds/arm/arch/arm/boot/zImage \
-append 'console=ttyAMA0 root=/dev/sda2 systemd.unit=benchmark.service' \
-snapshot"
It has a marginal effect on runtime, before:
Time (mean ± σ): 26.279 s ± 2.438 s [User: 41.113 s, System: 1.843 s]
Range (min … max): 24.420 s … 32.565 s 20 runs
after:
Time (mean ± σ): 24.440 s ± 2.885 s [User: 34.474 s, System: 2.028 s]
Range (min … max): 21.663 s … 29.937 s 20 runs
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1358
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20230526165401.574474-10-alex.bennee@linaro.org
Message-Id: <20230524133952.3971948-9-alex.bennee@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
71 lines
2.3 KiB
C
71 lines
2.3 KiB
C
/*
|
|
* internal execution defines for qemu
|
|
*
|
|
* Copyright (c) 2003 Fabrice Bellard
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifndef EXEC_TB_HASH_H
|
|
#define EXEC_TB_HASH_H
|
|
|
|
#include "exec/cpu-defs.h"
|
|
#include "exec/exec-all.h"
|
|
#include "qemu/xxhash.h"
|
|
#include "tb-jmp-cache.h"
|
|
|
|
#ifdef CONFIG_SOFTMMU
|
|
|
|
/* Only the bottom TB_JMP_PAGE_BITS of the jump cache hash bits vary for
|
|
addresses on the same page. The top bits are the same. This allows
|
|
TLB invalidation to quickly clear a subset of the hash table. */
|
|
#define TB_JMP_PAGE_BITS (TB_JMP_CACHE_BITS / 2)
|
|
#define TB_JMP_PAGE_SIZE (1 << TB_JMP_PAGE_BITS)
|
|
#define TB_JMP_ADDR_MASK (TB_JMP_PAGE_SIZE - 1)
|
|
#define TB_JMP_PAGE_MASK (TB_JMP_CACHE_SIZE - TB_JMP_PAGE_SIZE)
|
|
|
|
static inline unsigned int tb_jmp_cache_hash_page(target_ulong pc)
|
|
{
|
|
target_ulong tmp;
|
|
tmp = pc ^ (pc >> (TARGET_PAGE_BITS - TB_JMP_PAGE_BITS));
|
|
return (tmp >> (TARGET_PAGE_BITS - TB_JMP_PAGE_BITS)) & TB_JMP_PAGE_MASK;
|
|
}
|
|
|
|
static inline unsigned int tb_jmp_cache_hash_func(target_ulong pc)
|
|
{
|
|
target_ulong tmp;
|
|
tmp = pc ^ (pc >> (TARGET_PAGE_BITS - TB_JMP_PAGE_BITS));
|
|
return (((tmp >> (TARGET_PAGE_BITS - TB_JMP_PAGE_BITS)) & TB_JMP_PAGE_MASK)
|
|
| (tmp & TB_JMP_ADDR_MASK));
|
|
}
|
|
|
|
#else
|
|
|
|
/* In user-mode we can get better hashing because we do not have a TLB */
|
|
static inline unsigned int tb_jmp_cache_hash_func(target_ulong pc)
|
|
{
|
|
return (pc ^ (pc >> TB_JMP_CACHE_BITS)) & (TB_JMP_CACHE_SIZE - 1);
|
|
}
|
|
|
|
#endif /* CONFIG_SOFTMMU */
|
|
|
|
static inline
|
|
uint32_t tb_hash_func(tb_page_addr_t phys_pc, target_ulong pc,
|
|
uint32_t flags, uint32_t cf_mask)
|
|
{
|
|
return qemu_xxhash6(phys_pc, pc, flags, cf_mask);
|
|
}
|
|
|
|
#endif
|