[PATCH v4 24/29] trace-cmd: Compress trace data

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

When creating a trace.dat file of version 7, compress the trace data.
The data is compressed in chunks. The chunk size is a compile time
parameter, set by default to 1MB.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-output.c | 50 +++++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 046fa2d7..dbc956d4 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -321,6 +321,41 @@ static tsize_t copy_file(struct tracecmd_output *handle,
 	return size;
 }
 
+#define COMPRESS_CHUNK_SIZE (1*1024*1024)
+static tsize_t copy_file_compress(struct tracecmd_output *handle,
+				  const char *file, unsigned long long *write_size)
+{
+	unsigned long long rsize = 0;
+	unsigned long long wsize = 0;
+	tsize_t size;
+	int ret;
+	int fd;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0) {
+		tracecmd_warning("Can't read '%s'", file);
+		return 0;
+	}
+
+	if (handle->file_version >= 7) {
+		ret = tracecmd_compress_copy_from(handle->compress, fd,
+						  COMPRESS_CHUNK_SIZE, &rsize, &wsize);
+		if (ret < 0) {
+			tracecmd_warning("Can't compress '%s'", file);
+			close(fd);
+			return 0;
+		}
+		size = rsize;
+		*write_size = wsize;
+	} else {
+		size = copy_file_fd(handle, fd);
+		*write_size = size;
+	}
+
+	close(fd);
+	return size;
+}
+
 /*
  * Finds the path to the debugfs/tracing
  * Allocates the string and stores it.
@@ -1685,8 +1720,9 @@ int tracecmd_write_cpu_data(struct tracecmd_output *handle,
 	struct data_file_write *data_files = NULL;
 	off64_t offset;
 	unsigned long long endian8;
+	unsigned long long read_size;
+	unsigned long long write_size;
 	char *clock = NULL;
-	off64_t check_size;
 	char *file;
 	struct stat st;
 	int ret;
@@ -1742,11 +1778,11 @@ int tracecmd_write_cpu_data(struct tracecmd_output *handle,
 			fprintf(stderr, "CPU%d data recorded at offset=0x%llx\n",
 				i, (unsigned long long) data_files[i].data_offset);
 
-		check_size = copy_file(handle, cpu_data_files[i]);
-		if (check_size != data_files[i].file_size) {
+		read_size = copy_file_compress(handle, cpu_data_files[i], &write_size);
+		if (read_size != data_files[i].file_size) {
 			errno = EINVAL;
 			tracecmd_warning("did not match size of %lld to %lld",
-					 check_size, data_files[i].file_size);
+					 read_size, data_files[i].file_size);
 			goto out_free;
 		}
 		/* Write the real CPU data offset inthe file */
@@ -1756,14 +1792,14 @@ int tracecmd_write_cpu_data(struct tracecmd_output *handle,
 			goto out_free;
 		/* Write the real CPU data size in the file */
 		offset = lseek64(handle->fd, data_files[i].soffset, SEEK_SET);
-		endian8 = convert_endian_8(handle, check_size);
+		endian8 = convert_endian_8(handle, write_size);
 		if (do_write_check(handle, &endian8, 8))
 			goto out_free;
-		offset = data_files[i].data_offset + check_size;
+		offset = data_files[i].data_offset + write_size;
 		offset = lseek64(handle->fd, offset, SEEK_SET);
 		if (!tracecmd_get_quiet(handle))
 			fprintf(stderr, "    %llu bytes in size\n",
-				(unsigned long long)check_size);
+				(unsigned long long)write_size);
 	}
 
 	if (lseek64(handle->fd, 0, SEEK_END) == (off64_t)-1)
-- 
2.31.1