[PATCH V5] Improve the performance of --num-threads -d 31

[Atsushi Kumagai]

Hello Zhou,

>Hello Atsushi and Minfei,
>
>How about this version?

Thanks for making v5 patch.
I agree with the concept, but I have comments.

>> @@ -10223,6 +10281,20 @@ 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 < MAP_REGION * info->num_threads) {
>> +		MSG("There isn't enough memory for %d threads.\n", info->num_threads);

You assume only MAP_REGION is the extra memory consumption for multi thread.
However, there are other stuff allocated in each thread, e.g. BUF_PARALLEL(i)
and the buffer for compression calculated by calculate_len_buf_out().

Shouldn't we consider them ?

>> +
>> +		info->num_threads = MIN(info->num_threads % 2, limit_size % MAP_REGION);
>> +		MSG("--num_threads is set to %d.\n", info->num_threads);

What does "info->num_threads % 2" mean ?

>> +	}
>> +
>> +	limit_size = limit_size - MAP_REGION * info->num_threads;
>> +

This patch prioritizes the memory for multi thread since it is reserved first,
but I think enough cyclic buffer should be reserved first because it's for more
fundamental feature than multi-threading.


Thanks,
Atsushi Kumagai

>>   	/* 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..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;
>>
>
>
>
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