Hello Zhou,
>The origin implementation of --num-threads wastes a lot of time
>dealing with the filtered pages. So it has a great performance degradation
>when -d 31 is specified.
>The new implementation is just like the following:
> * The basic idea is producer producing page and consumer writing page.
> * Each producer have a page_flag_buf list which is used for storing page's description.
> * The size of page_flag_buf is little so it won't take too much memory.
> * And all producers will share a page_data_buf array which is used for storing page's compressed data.
> * The main thread is the consumer. It will find the next pfn and write it into file.
> * The next pfn is smallest pfn in all page_flag_buf.
>It won't waste time and memory for filtered page. So it has a good behaviour in -d 31.
>
>Some tests results:
>
> -l -c
>-d 31: 2.6 11.3 (without num-threads)
> num-threads origin new origin new
> 1 13.2 2.9 22.4 13.2
> 2 11.6 2.46 15.3 7.3
> 4 10.4 3.2 12.3 5.7
>-d 0: 32.7 151.2(without num-threads)
> 1 43.3 45.3 158.9 159.4
> 2 21.2 23.0 81.8 83.2
> 4 18.2 21.4 46.1 47.5
>
>These tests are executed in the second kernel with /proc/vmcore.
I appreciate your work, the effect looks great.
There are still some performance degradation depending on the dump level,
but the problem we discussed is "especially -d31 is too slow",
so I think this patch is enough for now.
BTW, I have some small comments for cleanup, please check below.
>---
> makedumpfile.c | 266 +++++++++++++++++++++++++++++++++++++++------------------
> makedumpfile.h | 26 +++---
> 2 files changed, 196 insertions(+), 96 deletions(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index fa0b779..8cf274b 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -3483,7 +3483,8 @@ initial_for_parallel()
> unsigned long page_data_buf_size;
> unsigned long limit_size;
> int page_data_num;
>- int i;
>+ struct page_flag *current;
>+ int i, j;
>
> len_buf_out = calculate_len_buf_out(info->page_size);
>
>@@ -3562,8 +3563,10 @@ initial_for_parallel()
> - MAP_REGION * info->num_threads) * 0.6;
>
> page_data_num = limit_size / page_data_buf_size;
>+ info->num_buffers = 3 * info->num_threads;
>
>- info->num_buffers = MIN(NUM_BUFFERS, page_data_num);
>+ info->num_buffers = MAX(info->num_buffers, NUM_BUFFERS);
>+ info->num_buffers = MIN(info->num_buffers, page_data_num);
>
> DEBUG_MSG("Number of struct page_data for produce/consume: %d\n",
> info->num_buffers);
>@@ -3588,6 +3591,36 @@ initial_for_parallel()
> }
>
> /*
>+ * initial page_flag for each thread
>+ */
>+ if ((info->page_flag_buf = malloc(sizeof(void *) * info->num_threads))
>+ == NULL) {
>+ MSG("Can't allocate memory for page_flag_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ memset(info->page_flag_buf, 0, sizeof(void *) * info->num_threads);
>+
>+ for (i = 0; i < info->num_threads; i++) {
>+ if ((info->page_flag_buf[i] = malloc(sizeof(struct page_flag))) == NULL) {
>+ MSG("Can't allocate memory for page_flag_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ current = info->page_flag_buf[i];
>+
>+ for (j = 1; j < NUM_BUFFERS; j++) {
>+ if ((current->next = calloc(0, sizeof(struct page_flag))) == NULL) {
>+ MSG("Can't allocate memory for data of page_data_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ current = current->next;
>+ }
>+ current->next = info->page_flag_buf[i];
>+ }
>+
>+ /*
> * initial fd_memory for threads
> */
> for (i = 0; i < info->num_threads; i++) {
>@@ -3612,7 +3645,8 @@ initial_for_parallel()
> void
> free_for_parallel()
> {
>- int i;
>+ int i, j;
>+ struct page_flag *current;
>
> if (info->threads != NULL) {
> for (i = 0; i < info->num_threads; i++) {
>@@ -3655,6 +3689,19 @@ free_for_parallel()
> free(info->page_data_buf);
> }
>
>+ if (info->page_flag_buf != NULL) {
>+ for (i = 0; i < info->num_threads; i++) {
>+ for (j = 0; j < NUM_BUFFERS; j++) {
>+ if (info->page_flag_buf[i] != NULL) {
>+ current = info->page_flag_buf[i];
>+ info->page_flag_buf[i] = current->next;
>+ free(current);
>+ }
>+ }
>+ }
>+ free(info->page_flag_buf);
>+ }
>+
> if (info->parallel_info == NULL)
> return;
>
>@@ -7076,10 +7123,10 @@ kdump_thread_function_cyclic(void *arg) {
> void *retval = PTHREAD_FAIL;
> struct thread_args *kdump_thread_args = (struct thread_args *)arg;
> struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
>+ struct page_flag *page_flag_buf = kdump_thread_args->page_flag_buf;
> struct cycle *cycle = kdump_thread_args->cycle;
>- int page_data_num = kdump_thread_args->page_data_num;
> mdf_pfn_t pfn;
>- int index;
>+ int index = kdump_thread_args->thread_num;
> int buf_ready;
> int dumpable;
> int fd_memory = 0;
>@@ -7125,47 +7172,48 @@ kdump_thread_function_cyclic(void *arg) {
> kdump_thread_args->thread_num);
> }
>
>- while (1) {
>- /* get next pfn */
>- pthread_mutex_lock(&info->current_pfn_mutex);
>- pfn = info->current_pfn;
>- info->current_pfn++;
>- pthread_mutex_unlock(&info->current_pfn_mutex);
>+ /* filtered page won't take anything
>+ * unfiltered zero page will only take a page_flag_buf
>+ * unfiltered non-zero page will take a page_flag_buf and a page_data_buf
>+ */
>+ while (page_flag_buf->pfn < kdump_thread_args->end_pfn) {
>+ buf_ready = FALSE;
>
>- if (pfn >= kdump_thread_args->end_pfn)
>- break;
>+ while (page_data_buf[index].used != 0 ||
>+ pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>+ index = (index + 1) % info->num_buffers;
>
>- index = -1;
>- buf_ready = FALSE;
>+ page_data_buf[index].used = 1;
>
> while (buf_ready == FALSE) {
> pthread_testcancel();
>-
>- index = pfn % page_data_num;
>-
>- if (pfn - info->consumed_pfn > info->num_buffers)
>- continue;
>-
>- if (page_data_buf[index].ready != 0)
>+ /* 1 means page_flag_buf is ready to be used */
>+ if (page_flag_buf->ready == 1)
> continue;
For status flag, enum is preferable to explaining a magic number by comment.
>
>- pthread_mutex_lock(&page_data_buf[index].mutex);
>+ /* get next pfn */
>+ pthread_mutex_lock(&info->current_pfn_mutex);
>+ pfn = info->current_pfn;
>+ info->current_pfn++;
>+ /* 2 means page_flag_buf is being filled */
>+ page_flag_buf->ready = 2;
>+ pthread_mutex_unlock(&info->current_pfn_mutex);
>
>- if (page_data_buf[index].ready != 0)
>- goto unlock;
>+ page_flag_buf->pfn = pfn;
>
>- buf_ready = TRUE;
>-
>- page_data_buf[index].pfn = pfn;
>- page_data_buf[index].ready = 1;
>+ if (pfn >= kdump_thread_args->end_pfn) {
>+ page_data_buf[index].used = 0;
>+ page_flag_buf->ready = 1;
>+ info->current_pfn--;
>+ break;
>+ }
>
> dumpable = is_dumpable(
> info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> pfn,
> cycle);
>- page_data_buf[index].dumpable = dumpable;
> if (!dumpable)
>- goto unlock;
>+ continue;
>
> if (!read_pfn_parallel(fd_memory, pfn, buf,
> &bitmap_memory_parallel,
>@@ -7178,11 +7226,11 @@ kdump_thread_function_cyclic(void *arg) {
>
> if ((info->dump_level & DL_EXCLUDE_ZERO)
> && is_zero_page(buf, info->page_size)) {
>- page_data_buf[index].zero = TRUE;
>- goto unlock;
>+ page_flag_buf->zero = TRUE;
>+ goto next;
> }
>
>- page_data_buf[index].zero = FALSE;
>+ page_flag_buf->zero = FALSE;
>
> /*
> * Compress the page data.
>@@ -7232,12 +7280,16 @@ kdump_thread_function_cyclic(void *arg) {
> page_data_buf[index].size = info->page_size;
> memcpy(page_data_buf[index].buf, buf, info->page_size);
> }
>-unlock:
>- pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ page_flag_buf->index = index;
>+ buf_ready = TRUE;
>+next:
>+ page_flag_buf->ready = 1;
>+ page_flag_buf = page_flag_buf->next;
>
> }
>- }
>
>+ pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ }
> retval = NULL;
>
> fail:
>@@ -7265,14 +7317,15 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> struct page_desc pd;
> struct timeval tv_start;
> struct timeval last, new;
>- unsigned long long consuming_pfn;
> pthread_t **threads = NULL;
> struct thread_args *kdump_thread_args = NULL;
> void *thread_result;
>- int page_data_num;
>+ int page_buf_num;
> struct page_data *page_data_buf = NULL;
> int i;
> int index;
>+ int end_count, consuming, check_count;
>+ mdf_pfn_t current_pfn, temp_pfn;
>
> if (info->flag_elf_dumpfile)
> return FALSE;
>@@ -7319,16 +7372,11 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> threads = info->threads;
> kdump_thread_args = info->kdump_thread_args;
>
>- page_data_num = info->num_buffers;
>+ page_buf_num = info->num_buffers;
> page_data_buf = info->page_data_buf;
>
>- for (i = 0; i < page_data_num; i++) {
>- /*
>- * producer will use pfn in page_data_buf to decide the
>- * consumed pfn
>- */
>- page_data_buf[i].pfn = start_pfn - 1;
>- page_data_buf[i].ready = 0;
>+ for (i = 0; i < page_buf_num; i++) {
>+ page_data_buf[i].used = 0;
> res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
> if (res != 0) {
> ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
>@@ -7342,8 +7390,9 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> kdump_thread_args[i].len_buf_out = len_buf_out;
> kdump_thread_args[i].start_pfn = start_pfn;
> kdump_thread_args[i].end_pfn = end_pfn;
>- kdump_thread_args[i].page_data_num = page_data_num;
>+ kdump_thread_args[i].page_buf_num = page_buf_num;
> kdump_thread_args[i].page_data_buf = page_data_buf;
>+ kdump_thread_args[i].page_flag_buf = info->page_flag_buf[i];
> kdump_thread_args[i].cycle = cycle;
>
> res = pthread_create(threads[i], NULL,
>@@ -7356,55 +7405,101 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> }
> }
>
>- consuming_pfn = start_pfn;
>- index = -1;
>+ while (1) {
>+ consuming = 0;
>+ check_count = 0;
>
>- gettimeofday(&last, NULL);
>+ /*
>+ * The basic idea is producer producing page and consumer writing page.
>+ * Each producer have a page_flag_buf list which is used for storing page's description.
>+ * The size of page_flag_buf is little so it won't take too much memory.
>+ * And all producers will share a page_data_buf array which is used for storing page's compressed data.
>+ * The main thread is the consumer. It will find the next pfn and write it into file.
>+ * The next pfn is smallest pfn in all page_flag_buf.
>+ */
>+ /*
>+ *
>+ */
I hope such garbage will be removed in the next version.
Thanks,
Atsushi Kumagai
>+ while (1) {
>+ current_pfn = end_pfn;
>+ end_count = 0;
>
>- while (consuming_pfn < end_pfn) {
>- index = consuming_pfn % page_data_num;
>+ /*
>+ * page_flag_buf is in circular linked list.
>+ * The array info->page_flag_buf[] records the current page_flag_buf in each thread's
>+ * page_flag_buf list.
>+ * consuming is used for recording in which thread the pfn is the smallest.
>+ * current_pfn is used for recording the value of pfn when checking the pfn.
>+ */
>+ for (i = 0; i < info->num_threads; i++) {
>
>- gettimeofday(&new, NULL);
>- if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>- ERRMSG("Can't get data of pfn %llx.\n", consuming_pfn);
>- goto out;
>- }
>+ /*
>+ * ready == 0 means the page_flag_buf haven't been used.
>+ * So we will skip it.
>+ */
>+ if (info->page_flag_buf[i]->ready == 0)
>+ continue;
>+ temp_pfn = info->page_flag_buf[i]->pfn;
>
>- /*
>- * check pfn first without mutex locked to reduce the time
>- * trying to lock the mutex
>- */
>- if (page_data_buf[index].pfn != consuming_pfn)
>- continue;
>+ /*
>+ * count how many threads have reached the end.
>+ */
>+ if (temp_pfn >= end_pfn) {
>+ end_count++;
>+ continue;
>+ }
>
>- if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>- continue;
>+ if (current_pfn < temp_pfn)
>+ continue;
>
>- /* check whether the found one is ready to be consumed */
>- if (page_data_buf[index].pfn != consuming_pfn ||
>- page_data_buf[index].ready != 1) {
>- goto unlock;
>+ check_count++;
>+ consuming = i;
>+ current_pfn = temp_pfn;
>+ }
>+
>+ /*
>+ * If all the threads have reached the end, we will finish writing.
>+ */
>+ if (end_count >= info->num_threads)
>+ goto finish;
>+
>+ /*
>+ * Since it has the probabilty that there is no page_flag_buf being ready,
>+ * we should recheck if it happens.
>+ */
>+ if (check_count == 0)
>+ continue;
>+
>+ /*
>+ * When we check the pfn in page_flag_buf, it may be being produced.
>+ * So we should wait until it is ready to use. And if the pfn is
>+ * different from the value when we check, we should rechoose the buf.
>+ */
>+ gettimeofday(&last, NULL);
>+ while (info->page_flag_buf[consuming]->ready != 1) {
>+ gettimeofday(&new, NULL);
>+ if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>+ ERRMSG("Can't get data of pfn.\n");
>+ goto out;
>+ }
>+ }
>+
>+ if (current_pfn == info->page_flag_buf[consuming]->pfn)
>+ break;
> }
>
> if ((num_dumped % per) == 0)
> print_progress(PROGRESS_COPY, num_dumped, info->num_dumpable);
>
>- /* next pfn is found, refresh last here */
>- last = new;
>- consuming_pfn++;
>- info->consumed_pfn++;
>- page_data_buf[index].ready = 0;
>-
>- if (page_data_buf[index].dumpable == FALSE)
>- goto unlock;
>-
> num_dumped++;
>
>- if (page_data_buf[index].zero == TRUE) {
>+
>+ if (info->page_flag_buf[consuming]->zero == TRUE) {
> if (!write_cache(cd_header, pd_zero, sizeof(page_desc_t)))
> goto out;
> pfn_zero++;
> } else {
>+ index = info->page_flag_buf[consuming]->index;
> pd.flags = page_data_buf[index].flags;
> pd.size = page_data_buf[index].size;
> pd.page_flags = 0;
>@@ -7420,12 +7515,12 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> */
> if (!write_cache(cd_page, page_data_buf[index].buf, pd.size))
> goto out;
>-
>+ page_data_buf[index].used = 0;
> }
>-unlock:
>- pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ info->page_flag_buf[consuming]->ready = 0;
>+ info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
>
> }
>-
>+finish:
> ret = TRUE;
> /*
> * print [100 %]
>@@ -7464,7 +7559,7 @@ out:
> }
>
> if (page_data_buf != NULL) {
>- for (i = 0; i < page_data_num; i++) {
>+ for (i = 0; i < page_buf_num; i++) {
> pthread_mutex_destroy(&page_data_buf[i].mutex);
> }
> }
>@@ -7564,6 +7659,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
> num_dumped++;
> if (!read_pfn(pfn, buf))
> goto out;
>+
> filter_data_buffer(buf, pfn_to_paddr(pfn), info->page_size);
>
> /*
>diff --git a/makedumpfile.h b/makedumpfile.h
>index e0b5bbf..7452e24 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -977,7 +977,7 @@ typedef unsigned long long int ulonglong;
> #define PAGE_DATA_NUM (50)
> #define WAIT_TIME (60 * 10)
> #define PTHREAD_FAIL ((void *)-2)
>-#define NUM_BUFFERS (50)
>+#define NUM_BUFFERS (20)
>
> struct mmap_cache {
> char *mmap_buf;
>@@ -985,28 +985,31 @@ struct mmap_cache {
> off_t mmap_end_offset;
> };
>
>+struct page_flag {
>+ mdf_pfn_t pfn;
>+ char zero;
>+ char ready;
>+ short index;
>+ struct page_flag *next;
>+};
>+
> struct page_data
> {
>- mdf_pfn_t pfn;
>- int dumpable;
>- int zero;
>- unsigned int flags;
>+ pthread_mutex_t mutex;
> long size;
> unsigned char *buf;
>- pthread_mutex_t mutex;
>- /*
>- * whether the page_data is ready to be consumed
>- */
>- int ready;
>+ int flags;
>+ int used;
> };
>
> struct thread_args {
> int thread_num;
> unsigned long len_buf_out;
> mdf_pfn_t start_pfn, end_pfn;
>- int page_data_num;
>+ int page_buf_num;
> struct cycle *cycle;
> struct page_data *page_data_buf;
>+ struct page_flag *page_flag_buf;
> };
>
> /*
>@@ -1295,6 +1298,7 @@ struct DumpInfo {
> pthread_t **threads;
> struct thread_args *kdump_thread_args;
> struct page_data *page_data_buf;
>+ struct page_flag **page_flag_buf;
> pthread_rwlock_t usemmap_rwlock;
> mdf_pfn_t current_pfn;
> pthread_mutex_t current_pfn_mutex;
>--
>1.8.3.1
>
>
>
>
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