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migration/xbzrle: Use i386 host/cpuinfo.h

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Perform the function selection once, and only if CONFIG_AVX512_OPT
is enabled.  Centralize the selection to xbzrle.c, instead of
spreading the init across 3 files.

Remove xbzrle-bench.c.  The benefit of being able to benchmark
the different implementations is less important than not peeking
into the internals of the implementation.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-05-17 20:00:30 -07:00
parent 1b48d0abdf
commit 7ba7db9fa1
6 changed files with 39 additions and 550 deletions
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34
migration/ram.c
View file

@ -90,34 +90,6 @@
#define RAM_SAVE_FLAG_MULTIFD_FLUSH 0x200
/* We can't use any flag that is bigger than 0x200 */
int (*xbzrle_encode_buffer_func)(uint8_t *, uint8_t *, int,
uint8_t *, int) = xbzrle_encode_buffer;
#if defined(CONFIG_AVX512BW_OPT)
#include "qemu/cpuid.h"
static void __attribute__((constructor)) init_cpu_flag(void)
{
unsigned max = __get_cpuid_max(0, NULL);
int a, b, c, d;
if (max >= 1) {
__cpuid(1, a, b, c, d);
/* We must check that AVX is not just available, but usable. */
if ((c & bit_OSXSAVE) && (c & bit_AVX) && max >= 7) {
int bv;
__asm("xgetbv" : "=a"(bv), "=d"(d) : "c"(0));
__cpuid_count(7, 0, a, b, c, d);
/* 0xe6:
* XCR0[7:5] = 111b (OPMASK state, upper 256-bit of ZMM0-ZMM15
* and ZMM16-ZMM31 state are enabled by OS)
* XCR0[2:1] = 11b (XMM state and YMM state are enabled by OS)
*/
if ((bv & 0xe6) == 0xe6 && (b & bit_AVX512BW)) {
xbzrle_encode_buffer_func = xbzrle_encode_buffer_avx512;
}
}
}
}
#endif
XBZRLECacheStats xbzrle_counters;
/* used by the search for pages to send */
@ -660,9 +632,9 @@ static int save_xbzrle_page(RAMState *rs, PageSearchStatus *pss,
memcpy(XBZRLE.current_buf, *current_data, TARGET_PAGE_SIZE);
/* XBZRLE encoding (if there is no overflow) */
encoded_len = xbzrle_encode_buffer_func(prev_cached_page, XBZRLE.current_buf,
TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
TARGET_PAGE_SIZE);
encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
TARGET_PAGE_SIZE);
/*
* Update the cache contents, so that it corresponds to the data

26
migration/xbzrle.c
View file

@ -17,8 +17,9 @@
#if defined(CONFIG_AVX512BW_OPT)
#include <immintrin.h>
#include "host/cpuinfo.h"
int __attribute__((target("avx512bw")))
static int __attribute__((target("avx512bw")))
xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
uint8_t *dst, int dlen)
{
@ -135,6 +136,29 @@ xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
}
return d;
}
static int xbzrle_encode_buffer_int(uint8_t *old_buf, uint8_t *new_buf,
int slen, uint8_t *dst, int dlen);
static int (*accel_func)(uint8_t *, uint8_t *, int, uint8_t *, int);
static void __attribute__((constructor)) init_accel(void)
{
unsigned info = cpuinfo_init();
if (info & CPUINFO_AVX512BW) {
accel_func = xbzrle_encode_buffer_avx512;
} else {
accel_func = xbzrle_encode_buffer_int;
}
}
int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
uint8_t *dst, int dlen)
{
return accel_func(old_buf, new_buf, slen, dst, dlen);
}
#define xbzrle_encode_buffer xbzrle_encode_buffer_int
#endif
/*

5
migration/xbzrle.h
View file

@ -18,8 +18,5 @@ int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
uint8_t *dst, int dlen);
int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen);
#if defined(CONFIG_AVX512BW_OPT)
int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
uint8_t *dst, int dlen);
#endif
#endif