[PATCH v7] Improve the performance of --num-threads -d 31

[Atsushi Kumagai]

>>v7:
>>	1. fix a bug pointed by Minfei Huang
>>v6:
>>        1. address Atsushi Kumagai's comments about calculating and reserving memory
>>v5:
>>        1. remove unused variable check_out
>>        2. reset num_threads if memory is not enough
>>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
>
>I have just one comment for this version:
>
>[snip]
>
>>@@ -10223,6 +10263,26 @@ calculate_cyclic_buffer_size(void) {
>> 	 *  free memory for safety.
>> 	 */
>> 	limit_size = get_free_memory_size() * 0.6;
>>+
>>+	/*
>>+	 * Recalculate the limit_size according to num_threads.
>>+	 * And reset num_threads if there is not enough memory.
>>+	 */
>>+	if (limit_size < maximun_size) {
                               ^
I found a typo.

>>+		if (info->num_threads > 0) {
>>+			MSG("There isn't enough memory for multi-threads.\n");
>>+			info->num_threads = 0;
>>+		}
>>+	}
>
>This condition should be "limit_size <= maximun_size", otherwise
>division by zero can occur below:
>
>
>>+	else if ((limit_size - maximum_size) / info->num_threads < THREAD_REGION) {
>                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Sorry, I misunderstood that.
However, you still should check info->num_threads, this patch causes division
by zero by default.


Thanks,
Atsushi Kumagai

>Thanks,
>Atsushi Kumagai
>
>>+		MSG("There isn't enough memory for %d threads.\n", info->num_threads);
>>+
>>+		info->num_threads = (limit_size - maximum_size) / THREAD_REGION;
>>+		MSG("--num_threads is set to %d.\n", info->num_threads);
>>+	}
>>+
>>+	limit_size = limit_size - THREAD_REGION * info->num_threads;
>>+
>> 	/* Try to keep both 1st and 2nd bitmap at the same time. */
>> 	bitmap_size = info->max_mapnr * 2 / BITPERBYTE;
>>
>>diff --git a/makedumpfile.h b/makedumpfile.h
>>index e0b5bbf..322d31b 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
>>@@ -974,10 +975,11 @@ typedef unsigned long long int ulonglong;
>>  * for parallel process
>>  */
>>
>>-#define PAGE_DATA_NUM	(50)
>>+#define PAGE_FLAG_NUM	(20)
>>+#define PAGE_DATA_NUM	(5)
>> #define WAIT_TIME	(60 * 10)
>> #define PTHREAD_FAIL	((void *)-2)
>>-#define NUM_BUFFERS	(50)
>>+#define THREAD_REGION	(200 * 1024)
>>
>> struct mmap_cache {
>> 	char	*mmap_buf;
>>@@ -985,28 +987,33 @@ 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 +1302,12 @@ 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
>>
>>
>>
>>
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