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target-arm: Use Neon for zero checking 

Use Neon instructions to perform zero checking of
buffer. This is helps in reducing total migration time.

Use case: Idle VM live migration with 4 VCPUS and 8GB ram
running CentOS 7.

Without Neon, the Total migration time is 3.5 Sec

Migration status: completed
total time: 3560 milliseconds
downtime: 33 milliseconds
setup: 5 milliseconds
transferred ram: 297907 kbytes
throughput: 685.76 mbps
remaining ram: 0 kbytes
total ram: 8519872 kbytes
duplicate: 2062760 pages
skipped: 0 pages
normal: 69808 pages
normal bytes: 279232 kbytes
dirty sync count: 3

With Neon, the total migration time is 2.9 Sec

Migration status: completed
total time: 2960 milliseconds
downtime: 65 milliseconds
setup: 4 milliseconds
transferred ram: 299869 kbytes
throughput: 830.19 mbps
remaining ram: 0 kbytes
total ram: 8519872 kbytes
duplicate: 2064313 pages
skipped: 0 pages
normal: 70294 pages
normal bytes: 281176 kbytes
dirty sync count: 3

Signed-off-by: Vijaya Kumar K <vijayak@cavium.com>
Signed-off-by: Suresh <ksuresh@cavium.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1467190029-694-2-git-send-email-vijayak@cavium.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Vijay 2016-07-14 16:51:36 +01:00 committed by Peter Maydell
parent 56215da394
commit 7069532e3b
1 changed files with 7 additions and 0 deletions
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7
util/cutils.c
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@ -184,6 +184,13 @@ int qemu_fdatasync(int fd)
#define SPLAT(p) _mm_set1_epi8(*(p))
#define ALL_EQ(v1, v2) (_mm_movemask_epi8(_mm_cmpeq_epi8(v1, v2)) == 0xFFFF)
#define VEC_OR(v1, v2) (_mm_or_si128(v1, v2))
#elif defined(__aarch64__)
#include "arm_neon.h"
#define VECTYPE uint64x2_t
#define ALL_EQ(v1, v2) \
((vgetq_lane_u64(v1, 0) == vgetq_lane_u64(v2, 0)) && \
(vgetq_lane_u64(v1, 1) == vgetq_lane_u64(v2, 1)))
#define VEC_OR(v1, v2) ((v1) | (v2))
#else
#define VECTYPE unsigned long
#define SPLAT(p) (*(p) * (~0UL / 255))