Re: [f2fs-dev] [PATCH] f2fs_io: add create_speed command

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

On 2025/6/13 12:02, Daniel Lee wrote:
> A new command 'create_speed', has been introduced to measure
> the performance of creating and deleting many files.
> 
> Signed-off-by: Daniel Lee <chullee@google.com>
> ---
>   tools/f2fs_io/f2fs_io.c | 112 ++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 112 insertions(+)
> 
> diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
> index 6531b55..ea6a3ff 100644
> --- a/tools/f2fs_io/f2fs_io.c
> +++ b/tools/f2fs_io/f2fs_io.c
> @@ -2092,6 +2092,117 @@ static void do_ftruncate(int argc, char **argv, const struct cmd_desc *cmd)
>   	exit(0);
>   }
>   
> +#define create_speed_desc "create_speed a file"
> +#define create_speed_help				\
> +"f2fs_io create_speed [dir] [num_files] [size_kb]\n\n"	\
> +"Measures file creation and deletion performance.\n"
> +
> +static void do_create_speed(int argc, char **argv, const struct cmd_desc *cmd)
> +{
> +	if (argc != 4) {
> +		fputs("Usage: f2fs_io create_latency <directory> <num_files> [size_kb]\n", stderr);
> +	fputs(cmd->cmd_help, stderr);
> +	exit(1);
> +	}
> +
> +	const char *dir = argv[1];
> +	int num_files = atoi(argv[2]);
> +	int size_kb = atoi(argv[3]);
> +	char *write_buffer = NULL;
> +
> +	if (num_files <= 0) {
> +		fprintf(stderr, "Error: Number of files must be positive.\n");
> +	exit(1);
> +	}
> +
> +	if (size_kb > 0) {
> +		write_buffer = malloc(size_kb * 1024);
> +		if (!write_buffer) {
> +			perror("Failed to allocate write buffer");
> +			exit(1);
> +		}
> +		memset(write_buffer, 'a', size_kb * 1024);
> +	}
> +
> +	// Creation Phase
> +	printf("Starting test: Creating %d files of %dKB each in %s\n", num_files, size_kb, dir);
> +
> +	struct timespec create_start, create_end;
> +
> +	clock_gettime(CLOCK_MONOTONIC, &create_start);
> +
> +	for (int i = 0; i < num_files; i++) {
> +		char path[1024];
> +
> +		snprintf(path, sizeof(path), "%s/test_file_%d", dir, i);
> +
> +		int fd = open(path, O_WRONLY | O_CREAT, 0644);
> +
> +		if (fd < 0) {
> +			perror("Error opening file");
> +			continue;
> +		}
> +		if (size_kb > 0) {
> +			if (write(fd, write_buffer, size_kb * 1024) < 0)
> +				perror("Error writing to file");
> +		}
> +		if (fsync(fd) < 0)

Maybe we need to call fsync() optionally, as if we want to find and
notice performance regression comes from create, we'd better avoid
distraction from disk IO.

Thanks,

> +			perror("Error fsyncing file");
> +
> +		close(fd);
> +	}
> +
> +	clock_gettime(CLOCK_MONOTONIC, &create_end);
> +
> +
> +	// Deletion Phase
> +	printf("Deleting %d created files...\n", num_files);
> +
> +	struct timespec del_start, del_end;
> +
> +	clock_gettime(CLOCK_MONOTONIC, &del_start);
> +
> +	for (int i = 0; i < num_files; i++) {
> +		char path[1024];
> +
> +		snprintf(path, sizeof(path), "%s/test_file_%d", dir, i);
> +		if (unlink(path) != 0)
> +			perror("Error unlinking file");
> +	}
> +	sync();
> +
> +	clock_gettime(CLOCK_MONOTONIC, &del_end);
> +
> +	long create_seconds = create_end.tv_sec - create_start.tv_sec;
> +	long create_ns = create_end.tv_nsec - create_start.tv_nsec;
> +	double create_time_s = (double)create_seconds + (double)create_ns / 1000000000.0;
> +	double create_throughput = (create_time_s > 0) ? (num_files / create_time_s) : 0;
> +
> +	long del_seconds = del_end.tv_sec - del_start.tv_sec;
> +	long del_ns = del_end.tv_nsec - del_start.tv_nsec;
> +	double del_time_s = (double)del_seconds + (double)del_ns / 1000000000.0;
> +	double del_throughput = (del_time_s > 0) ? (num_files / del_time_s) : 0;
> +
> +	printf("Operation,total_files,file_size_kb,total_time_s,throughput_files_per_sec\n");
> +
> +	printf("CREATE,%d,%d,%.4f,%.2f\n",
> +		   num_files,
> +		   size_kb,
> +		   create_time_s,
> +		   create_throughput);
> +
> +	printf("DELETE,%d,%d,%.4f,%.2f\n",
> +		   num_files,
> +		   size_kb,
> +		   del_time_s,
> +		   del_throughput);
> +
> +	if (write_buffer)
> +		free(write_buffer);
> +
> +	exit(0);
> +}
> +
>   #define CMD_HIDDEN 	0x0001
>   #define CMD(name) { #name, do_##name, name##_desc, name##_help, 0 }
>   #define _CMD(name) { #name, do_##name, NULL, NULL, CMD_HIDDEN }
> @@ -2140,6 +2251,7 @@ const struct cmd_desc cmd_list[] = {
>   	CMD(get_advise),
>   	CMD(ioprio),
>   	CMD(ftruncate),
> +	CMD(create_speed),
>   	{ NULL, NULL, NULL, NULL, 0 }
>   };
>   



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