[PATCH v4] Improve the performance of --num-threads -d 31
Minfei Huang
mhuang at redhat.com
Mon Mar 14 23:34:30 PDT 2016
Hi, Zhou.
I have applied this patch base on 1.5.9. There are several testcases I
have tested.
- makedumpfile --num-threads 64 -d 31
real 0m0.010s
user 0m0.002s
sys 0m0.009s
- makedumpfile --num-threads 31 -d 31
real 2m40.915s
user 10m50.900s
sys 23m9.664s
makedumpfile --num-threads 30 -d 31
real 0m0.006s
user 0m0.002s
sys 0m0.004s
makedumpfile --num-threads 32 -d 31
real 0m0.007s
user 0m0.002s
sys 0m0.005s
- makedumpfile --num-threads 8 -d 31
real 2m32.692s
user 7m4.630s
sys 2m0.369s
- makedumpfile --num-threads 1 -d 31
real 4m42.423s
user 7m27.153s
sys 0m22.490s
- makedumpfile.orig -d 31
real 4m1.297s
user 3m39.696s
sys 0m15.200s
This patch has a huge increment to the filter performance under 31. But
it is not stable, since makedumpfile fails to dump vmcore intermittently.
You can find the above test result, makedumpfile fails to dump vmcore
with option --num-threads 64, also it may occur with option
--number-threads 8.
Thanks
Minfei
On 03/09/16 at 08:27am, Zhou Wenjian wrote:
> v4:
> 1. fix a bug caused by the logic
> v3:
> 1. remove some unused variables
> 2. fix a bug caused by the wrong logic
> 3. fix a bug caused by optimising
> 4. improve more performance by using Minoru Usui's code
>
> multi-threads implementation will introduce extra cost when handling
> each page. The origin implementation will also do the extra work for
> filtered pages. So there is a big performance degradation in
> --num-threads -d 31.
> The new implementation won't do the extra work for filtered pages any
> more. So the performance of -d 31 is close to that of serial processing.
>
> 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.
>
> Signed-off-by: Minoru Usui <min-usui at ti.jp.nec.com>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com>
> ---
> makedumpfile.c | 298 +++++++++++++++++++++++++++++++++++----------------------
> makedumpfile.h | 35 ++++---
> 2 files changed, 202 insertions(+), 131 deletions(-)
>
> diff --git a/makedumpfile.c b/makedumpfile.c
> index fa0b779..2b0864a 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);
>
> @@ -3560,10 +3561,16 @@ initial_for_parallel()
>
> limit_size = (get_free_memory_size()
> - MAP_REGION * info->num_threads) * 0.6;
> + if (limit_size < 0) {
> + MSG("Free memory is not enough for multi-threads\n");
> + return FALSE;
> + }
>
> 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 +3595,36 @@ 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] = calloc(1, sizeof(struct page_flag))) == NULL) {
> + MSG("Can't allocate memory for page_flag. %s\n",
> + strerror(errno));
> + return FALSE;
> + }
> + current = info->page_flag_buf[i];
> +
> + for (j = 1; j < NUM_BUFFERS; j++) {
> + if ((current->next = calloc(1, sizeof(struct page_flag))) == NULL) {
> + MSG("Can't allocate memory for page_flag. %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 +3649,8 @@ 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 +3693,19 @@ 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;
>
> @@ -7075,11 +7126,11 @@ void *
> 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;
> + volatile struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
> + volatile 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;
> + mdf_pfn_t pfn = cycle->start_pfn;
> + int index = kdump_thread_args->thread_num;
> int buf_ready;
> int dumpable;
> int fd_memory = 0;
> @@ -7125,47 +7176,48 @@ 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);
> -
> - if (pfn >= kdump_thread_args->end_pfn)
> - break;
> -
> - index = -1;
> + /*
> + * 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 (pfn < cycle->end_pfn) {
> buf_ready = FALSE;
>
> + pthread_mutex_lock(&info->page_data_mutex);
> + while (page_data_buf[index].used != FALSE) {
> + index = (index + 1) % info->num_buffers;
> + }
> + page_data_buf[index].used = TRUE;
> + pthread_mutex_unlock(&info->page_data_mutex);
> +
> while (buf_ready == FALSE) {
> pthread_testcancel();
> -
> - index = pfn % page_data_num;
> -
> - if (pfn - info->consumed_pfn > info->num_buffers)
> + if (page_flag_buf->ready == FLAG_READY)
> continue;
>
> - if (page_data_buf[index].ready != 0)
> - continue;
> -
> - pthread_mutex_lock(&page_data_buf[index].mutex);
> -
> - if (page_data_buf[index].ready != 0)
> - goto unlock;
> -
> - buf_ready = TRUE;
> + /* get next dumpable pfn */
> + pthread_mutex_lock(&info->current_pfn_mutex);
> + for (pfn = info->current_pfn; pfn < cycle->end_pfn; pfn++) {
> + dumpable = is_dumpable(
> + info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> + pfn,
> + cycle);
> + if (dumpable)
> + break;
> + }
> + info->current_pfn = pfn + 1;
>
> - page_data_buf[index].pfn = pfn;
> - page_data_buf[index].ready = 1;
> + page_flag_buf->pfn = pfn;
> + page_flag_buf->ready = FLAG_FILLING;
> + pthread_mutex_unlock(&info->current_pfn_mutex);
> + sem_post(&info->page_flag_buf_sem);
>
> - dumpable = is_dumpable(
> - info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> - pfn,
> - cycle);
> - page_data_buf[index].dumpable = dumpable;
> - if (!dumpable)
> - goto unlock;
> + if (pfn >= cycle->end_pfn) {
> + info->current_pfn = cycle->end_pfn;
> + page_data_buf[index].used = FALSE;
> + break;
> + }
>
> if (!read_pfn_parallel(fd_memory, pfn, buf,
> &bitmap_memory_parallel,
> @@ -7178,11 +7230,11 @@ 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.
> @@ -7210,6 +7262,7 @@ kdump_thread_function_cyclic(void *arg) {
> page_data_buf[index].flags =
> DUMP_DH_COMPRESSED_LZO;
> page_data_buf[index].size = size_out;
> +
> memcpy(page_data_buf[index].buf, buf_out, size_out);
> #endif
> #ifdef USESNAPPY
> @@ -7232,12 +7285,14 @@ 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 = FLAG_READY;
> + page_flag_buf = page_flag_buf->next;
>
> }
> }
> -
> retval = NULL;
>
> fail:
> @@ -7265,14 +7320,15 @@ 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;
> @@ -7284,13 +7340,6 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> goto out;
> }
>
> - res = pthread_mutex_init(&info->consumed_pfn_mutex, NULL);
> - if (res != 0) {
> - ERRMSG("Can't initialize consumed_pfn_mutex. %s\n",
> - strerror(res));
> - goto out;
> - }
> -
> res = pthread_mutex_init(&info->filter_mutex, NULL);
> if (res != 0) {
> ERRMSG("Can't initialize filter_mutex. %s\n", strerror(res));
> @@ -7314,36 +7363,23 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> end_pfn = cycle->end_pfn;
>
> info->current_pfn = start_pfn;
> - info->consumed_pfn = start_pfn - 1;
>
> 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;
> + pthread_mutex_init(&info->page_data_mutex, NULL);
> + sem_init(&info->page_flag_buf_sem, 0, 0);
>
> - 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;
> - res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
> - if (res != 0) {
> - ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
> - strerror(res));
> - goto out;
> - }
> - }
> + for (i = 0; i < page_buf_num; i++)
> + page_data_buf[i].used = FALSE;
>
> for (i = 0; i < info->num_threads; i++) {
> kdump_thread_args[i].thread_num = i;
> 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_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 +7392,88 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> }
> }
>
> - consuming_pfn = start_pfn;
> - index = -1;
> + end_count = 0;
> + 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.
> + */
> + sem_wait(&info->page_flag_buf_sem);
> + gettimeofday(&last, NULL);
> + while (1) {
> + current_pfn = end_pfn;
>
> - 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++) {
> + if (info->page_flag_buf[i]->ready == FLAG_UNUSED)
> + continue;
> + temp_pfn = info->page_flag_buf[i]->pfn;
>
> - 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;
> - }
> + /*
> + * count how many threads have reached the end.
> + */
> + if (temp_pfn >= end_pfn) {
> + info->page_flag_buf[i]->ready = FLAG_UNUSED;
> + end_count++;
> + continue;
> + }
>
> - /*
> - * check pfn first without mutex locked to reduce the time
> - * trying to lock the mutex
> - */
> - if (page_data_buf[index].pfn != consuming_pfn)
> - continue;
> + if (current_pfn < temp_pfn)
> + continue;
>
> - if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
> - continue;
> + check_count++;
> + consuming = i;
> + current_pfn = temp_pfn;
> + }
>
> - /* 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;
> + /*
> + * If all the threads have reached the end, we will finish writing.
> + */
> + if (end_count >= info->num_threads)
> + goto finish;
> +
> + /*
> + * If the page_flag_buf is not ready, the pfn recorded may be changed.
> + * So we should recheck.
> + */
> + if (info->page_flag_buf[consuming]->ready != FLAG_READY) {
> + gettimeofday(&new, NULL);
> + if (new.tv_sec - last.tv_sec > WAIT_TIME) {
> + ERRMSG("Can't get data of pfn.\n");
> + goto out;
> + }
> + continue;
> + }
> +
> + 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 +7489,12 @@ 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 = FALSE;
> }
> -unlock:
> - pthread_mutex_unlock(&page_data_buf[index].mutex);
> + info->page_flag_buf[consuming]->ready = FLAG_UNUSED;
> + info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
> }
> -
> +finish:
> ret = TRUE;
> /*
> * print [100 %]
> @@ -7463,15 +7532,9 @@ out:
> }
> }
>
> - if (page_data_buf != NULL) {
> - for (i = 0; i < page_data_num; i++) {
> - pthread_mutex_destroy(&page_data_buf[i].mutex);
> - }
> - }
> -
> + sem_destroy(&info->page_flag_buf_sem);
> pthread_rwlock_destroy(&info->usemmap_rwlock);
> pthread_mutex_destroy(&info->filter_mutex);
> - pthread_mutex_destroy(&info->consumed_pfn_mutex);
> pthread_mutex_destroy(&info->current_pfn_mutex);
>
> return ret;
> @@ -7564,6 +7627,7 @@ 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..4b315c0 100644
> --- a/makedumpfile.h
> +++ b/makedumpfile.h
> @@ -44,6 +44,7 @@
> #include "print_info.h"
> #include "sadump_mod.h"
> #include <pthread.h>
> +#include <semaphore.h>
>
> /*
> * Result of command
> @@ -977,7 +978,7 @@ 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 +986,33 @@ struct mmap_cache {
> off_t mmap_end_offset;
> };
>
> +enum {
> + FLAG_UNUSED,
> + FLAG_READY,
> + FLAG_FILLING
> +};
> +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;
> 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;
> struct cycle *cycle;
> struct page_data *page_data_buf;
> + struct page_flag *page_flag_buf;
> };
>
> /*
> @@ -1295,11 +1301,12 @@ struct DumpInfo {
> pthread_t **threads;
> struct thread_args *kdump_thread_args;
> struct page_data *page_data_buf;
> + struct page_flag **page_flag_buf;
> + sem_t page_flag_buf_sem;
> pthread_rwlock_t usemmap_rwlock;
> mdf_pfn_t current_pfn;
> pthread_mutex_t current_pfn_mutex;
> - mdf_pfn_t consumed_pfn;
> - pthread_mutex_t consumed_pfn_mutex;
> + pthread_mutex_t page_data_mutex;
> pthread_mutex_t filter_mutex;
> };
> extern struct DumpInfo *info;
> --
> 1.8.3.1
>
>
>
>
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
More information about the kexec
mailing list