[PATCH v3] Improve the performance of --num-threads -d 31
Minoru Usui
min-usui at ti.jp.nec.com
Sun Mar 6 23:36:34 PST 2016
Hi, Minfei, Zhou
> -----Original Message-----
> From: kexec [mailto:kexec-bounces at lists.infradead.org] On Behalf Of Minfei Huang
> Sent: Monday, March 07, 2016 4:05 PM
> To: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com>
> Cc: kexec at lists.infradead.org
> Subject: Re: [PATCH v3] Improve the performance of --num-threads -d 31
>
> Hi, Wenjian.
>
> Since your patch applied Minoru Usui's draft patch, I have vierified it.
> And it works well under 4T memory.
>
> applied makedumpfile with option -d 31
> real 3m48.681s
>
> applied makedumpfile with option -d 31 --num-threads 32
> real 3m3.533s
>
> original makedumpfile with option -d 31
> real 3m57.163s
>
> Now with or without option --num-thread, it takes almost same time.
Thank you for your test on big memory machine.
I am relieved to see your test results.
Zhou, my patch may not be sophisticated,
but getting mutex logic is robust, it works well and its performance is not bad.
I think it reaches the goal of the original purpose.
I understand you don't like getting mutex, but if you are debugging now, could you apply my approach?
Thanks,
Minoru Usui
> Thanks
> Minfei
>
> On 03/04/16 at 04:35pm, Zhou Wenjian wrote:
> > 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 | 300 +++++++++++++++++++++++++++++++++++----------------------
> > makedumpfile.h | 33 ++++---
> > 2 files changed, 203 insertions(+), 130 deletions(-)
> >
> > diff --git a/makedumpfile.c b/makedumpfile.c
> > index fa0b779..d75f7f7 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)
> > - continue;
> > -
> > - if (page_data_buf[index].ready != 0)
> > + if (page_flag_buf->ready == FLAG_READY)
> > continue;
> >
> > - pthread_mutex_lock(&page_data_buf[index].mutex);
> > -
> > - if (page_data_buf[index].ready != 0)
> > - goto unlock;
> > + /* 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;
> >
> > - buf_ready = TRUE;
> > + page_flag_buf->pfn = pfn;
> > + page_flag_buf->ready = FLAG_FILLING;
> > + pthread_mutex_unlock(&info->current_pfn_mutex);
> >
> > - page_data_buf[index].pfn = pfn;
> > - page_data_buf[index].ready = 1;
> >
> > - 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 +7363,22 @@ 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);
> >
> > - 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 +7391,94 @@ 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.
> > + */
> > + 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;
> > + }
> > +
> > + /*
> > + * 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;
> > +
> > + /*
> > + * 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;
> > + }
> >
> > - /* 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 (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 +7494,12 @@ 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 +7537,8 @@ out:
> > }
> > }
> >
> > - if (page_data_buf != NULL) {
> > - for (i = 0; i < page_data_num; i++) {
> > - pthread_mutex_destroy(&page_data_buf[i].mutex);
> > - }
> > - }
> > -
> > 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 +7631,7 @@ 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..5865827 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 +985,33 @@ 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 +1300,11 @@ 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;
> > - 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
>
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