From: Hao Xiang <hao.xi...@linux.dev> Multifd sender path gets an array of pages queued by the migration thread. It performs zero page checking on every page in the array. The pages are classfied as either a zero page or a normal page. This change uses Intel DSA to offload the zero page checking from CPU to the DSA accelerator. The sender thread submits a batch of pages to DSA hardware and waits for the DSA completion thread to signal for work completion.
Signed-off-by: Hao Xiang <hao.xi...@linux.dev> Signed-off-by: Yichen Wang <yichen.w...@bytedance.com> --- migration/multifd-zero-page.c | 149 ++++++++++++++++++++++++++++++---- migration/multifd.c | 15 +++- migration/multifd.h | 6 ++ migration/options.c | 13 +++ migration/options.h | 1 + 5 files changed, 168 insertions(+), 16 deletions(-) diff --git a/migration/multifd-zero-page.c b/migration/multifd-zero-page.c index f1e988a959..08e7fc3d92 100644 --- a/migration/multifd-zero-page.c +++ b/migration/multifd-zero-page.c @@ -21,7 +21,9 @@ static bool multifd_zero_page_enabled(void) { - return migrate_zero_page_detection() == ZERO_PAGE_DETECTION_MULTIFD; + ZeroPageDetection curMethod = migrate_zero_page_detection(); + return (curMethod == ZERO_PAGE_DETECTION_MULTIFD || + curMethod == ZERO_PAGE_DETECTION_DSA_ACCEL); } static void swap_page_offset(ram_addr_t *pages_offset, int a, int b) @@ -37,26 +39,49 @@ static void swap_page_offset(ram_addr_t *pages_offset, int a, int b) pages_offset[b] = temp; } +#ifdef CONFIG_DSA_OPT + +static void swap_result(bool *results, int a, int b) +{ + bool temp; + + if (a == b) { + return; + } + + temp = results[a]; + results[a] = results[b]; + results[b] = temp; +} + /** - * multifd_send_zero_page_detect: Perform zero page detection on all pages. + * zero_page_detect_dsa: Perform zero page detection using + * Intel Data Streaming Accelerator (DSA). * - * Sorts normal pages before zero pages in p->pages->offset and updates - * p->pages->normal_num. + * Sorts normal pages before zero pages in pages->offset and updates + * pages->normal_num. * * @param p A pointer to the send params. */ -void multifd_send_zero_page_detect(MultiFDSendParams *p) +static void zero_page_detect_dsa(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; RAMBlock *rb = pages->block; - int i = 0; - int j = pages->num - 1; + bool *results = p->dsa_batch_task->results; - if (!multifd_zero_page_enabled()) { - pages->normal_num = pages->num; - goto out; + for (int i = 0; i < pages->num; i++) { + p->dsa_batch_task->addr[i] = + (ram_addr_t)(rb->host + pages->offset[i]); } + buffer_is_zero_dsa_batch_sync(p->dsa_batch_task, + (const void **)p->dsa_batch_task->addr, + pages->num, + multifd_ram_page_size()); + + int i = 0; + int j = pages->num - 1; + /* * Sort the page offset array by moving all normal pages to * the left and all zero pages to the right of the array. @@ -64,23 +89,59 @@ void multifd_send_zero_page_detect(MultiFDSendParams *p) while (i <= j) { uint64_t offset = pages->offset[i]; - if (!buffer_is_zero(rb->host + offset, multifd_ram_page_size())) { + if (!results[i]) { i++; continue; } + swap_result(results, i, j); swap_page_offset(pages->offset, i, j); ram_release_page(rb->idstr, offset); j--; } pages->normal_num = i; +} -out: - stat64_add(&mig_stats.normal_pages, pages->normal_num); - stat64_add(&mig_stats.zero_pages, pages->num - pages->normal_num); +int multifd_dsa_setup(MigrationState *s, Error *local_err) +{ + g_autofree strList *dsa_parameter = g_malloc0(sizeof(strList)); + migrate_dsa_accel_path(dsa_parameter); + if (qemu_dsa_init(dsa_parameter, &local_err)) { + migrate_set_error(s, local_err); + return -1; + } else { + qemu_dsa_start(); + } + + return 0; +} + +void multifd_dsa_cleanup(void) +{ + qemu_dsa_cleanup(); +} + +#else + +static void zero_page_detect_dsa(MultiFDSendParams *p) +{ + g_assert_not_reached(); } +int multifd_dsa_setup(MigrationState *s, Error *local_err) +{ + g_assert_not_reached(); + return -1; +} + +void multifd_dsa_cleanup(void) +{ + return ; +} + +#endif + void multifd_recv_zero_page_process(MultiFDRecvParams *p) { for (int i = 0; i < p->zero_num; i++) { @@ -92,3 +153,63 @@ void multifd_recv_zero_page_process(MultiFDRecvParams *p) } } } + +/** + * zero_page_detect_cpu: Perform zero page detection using CPU. + * + * Sorts normal pages before zero pages in p->pages->offset and updates + * p->pages->normal_num. + * + * @param p A pointer to the send params. + */ +static void zero_page_detect_cpu(MultiFDSendParams *p) +{ + MultiFDPages_t *pages = &p->data->u.ram; + RAMBlock *rb = pages->block; + int i = 0; + int j = pages->num - 1; + + /* + * Sort the page offset array by moving all normal pages to + * the left and all zero pages to the right of the array. + */ + while (i <= j) { + uint64_t offset = pages->offset[i]; + + if (!buffer_is_zero(rb->host + offset, multifd_ram_page_size())) { + i++; + continue; + } + + swap_page_offset(pages->offset, i, j); + ram_release_page(rb->idstr, offset); + j--; + } + + pages->normal_num = i; +} + +/** + * multifd_send_zero_page_detect: Perform zero page detection on all pages. + * + * @param p A pointer to the send params. + */ +void multifd_send_zero_page_detect(MultiFDSendParams *p) +{ + MultiFDPages_t *pages = &p->data->u.ram; + + if (!multifd_zero_page_enabled()) { + pages->normal_num = pages->num; + goto out; + } + + if (qemu_dsa_is_running()) { + zero_page_detect_dsa(p); + } else { + zero_page_detect_cpu(p); + } + +out: + stat64_add(&mig_stats.normal_pages, pages->normal_num); + stat64_add(&mig_stats.zero_pages, pages->num - pages->normal_num); +} diff --git a/migration/multifd.c b/migration/multifd.c index 498e71fd10..946144fc2f 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -13,6 +13,7 @@ #include "qemu/osdep.h" #include "qemu/cutils.h" #include "qemu/rcu.h" +#include "qemu/dsa.h" #include "exec/target_page.h" #include "sysemu/sysemu.h" #include "exec/ramblock.h" @@ -462,6 +463,8 @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) p->name = NULL; g_free(p->data); p->data = NULL; + buffer_zero_batch_task_destroy(p->dsa_batch_task); + p->dsa_batch_task = NULL; p->packet_len = 0; g_free(p->packet); p->packet = NULL; @@ -493,6 +496,8 @@ void multifd_send_shutdown(void) multifd_send_terminate_threads(); + multifd_dsa_cleanup(); + for (i = 0; i < migrate_multifd_channels(); i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; Error *local_err = NULL; @@ -814,11 +819,17 @@ bool multifd_send_setup(void) uint32_t page_count = multifd_ram_page_count(); bool use_packets = multifd_use_packets(); uint8_t i; + Error *local_err = NULL; if (!migrate_multifd()) { return true; } + if (s && + s->parameters.zero_page_detection == ZERO_PAGE_DETECTION_DSA_ACCEL) { + ret = multifd_dsa_setup(s, local_err); + } + thread_count = migrate_multifd_channels(); multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); multifd_send_state->params = g_new0(MultiFDSendParams, thread_count); @@ -829,12 +840,12 @@ bool multifd_send_setup(void) for (i = 0; i < thread_count; i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; - Error *local_err = NULL; qemu_sem_init(&p->sem, 0); qemu_sem_init(&p->sem_sync, 0); p->id = i; p->data = multifd_send_data_alloc(); + p->dsa_batch_task = buffer_zero_batch_task_init(page_count); if (use_packets) { p->packet_len = sizeof(MultiFDPacket_t) @@ -865,7 +876,6 @@ bool multifd_send_setup(void) for (i = 0; i < thread_count; i++) { MultiFDSendParams *p = &multifd_send_state->params[i]; - Error *local_err = NULL; ret = multifd_send_state->ops->send_setup(p, &local_err); if (ret) { @@ -1047,6 +1057,7 @@ void multifd_recv_cleanup(void) qemu_thread_join(&p->thread); } } + multifd_dsa_cleanup(); for (i = 0; i < migrate_multifd_channels(); i++) { multifd_recv_cleanup_channel(&multifd_recv_state->params[i]); } diff --git a/migration/multifd.h b/migration/multifd.h index 50d58c0c9c..da53b0bdfd 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -15,6 +15,7 @@ #include "exec/target_page.h" #include "ram.h" +#include "qemu/dsa.h" typedef struct MultiFDRecvData MultiFDRecvData; typedef struct MultiFDSendData MultiFDSendData; @@ -155,6 +156,9 @@ typedef struct { bool pending_sync; MultiFDSendData *data; + /* Zero page checking batch task */ + QemuDsaBatchTask *dsa_batch_task; + /* thread local variables. No locking required */ /* pointer to the packet */ @@ -313,6 +317,8 @@ void multifd_send_fill_packet(MultiFDSendParams *p); bool multifd_send_prepare_common(MultiFDSendParams *p); void multifd_send_zero_page_detect(MultiFDSendParams *p); void multifd_recv_zero_page_process(MultiFDRecvParams *p); +int multifd_dsa_setup(MigrationState *s, Error *local_err); +void multifd_dsa_cleanup(void); static inline void multifd_send_prepare_header(MultiFDSendParams *p) { diff --git a/migration/options.c b/migration/options.c index ca89fdc4f4..cc40d3dfea 100644 --- a/migration/options.c +++ b/migration/options.c @@ -817,6 +817,19 @@ const strList *migrate_accel_path(void) return s->parameters.accel_path; } +void migrate_dsa_accel_path(strList *dsa_accel_path) +{ + MigrationState *s = migrate_get_current(); + strList *accel_path = s->parameters.accel_path; + strList **tail = &dsa_accel_path; + while (accel_path) { + if (strncmp(accel_path->value, "dsa:", 4) == 0) { + QAPI_LIST_APPEND(tail, &accel_path->value[4]); + } + accel_path = accel_path->next; + } +} + const char *migrate_tls_hostname(void) { MigrationState *s = migrate_get_current(); diff --git a/migration/options.h b/migration/options.h index 3d1e91dc52..5e34b7c997 100644 --- a/migration/options.h +++ b/migration/options.h @@ -85,6 +85,7 @@ const char *migrate_tls_hostname(void); uint64_t migrate_xbzrle_cache_size(void); ZeroPageDetection migrate_zero_page_detection(void); const strList *migrate_accel_path(void); +void migrate_dsa_accel_path(strList *dsa_accel_path); /* parameters helpers */ -- Yichen Wang