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Use mmap to read from the pathlist file for performance.

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This commit is contained in:
Moinak Ghosh 2013-11-02 12:14:46 +05:30
parent dcccffd7fa
commit a374ca5909
3 changed files with 83 additions and 7 deletions
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78
archive/pc_archive.c
View file

@ -66,6 +66,7 @@ AE_IFIFO Named pipe (fifo)
#define MMAP_SIZE (1024 * 1024)
#define SORT_BUF_SIZE (65536)
#define NAMELEN 4
#define TEMP_MMAP_SIZE (128 * 1024)
typedef struct member_entry {
char name[NAMELEN];
@ -138,11 +139,12 @@ compare_members_lt(member_entry_t *mem1, member_entry_t *mem2) {
* Fetch the next entry from the pathlist file. If we are doing sorting then this
* fetches the next entry in ascending order of the predetermined sort keys.
*/
int
read_next(pc_ctx_t *pctx, char *fpath)
static int
read_next_path(pc_ctx_t *pctx, char *fpath)
{
short namelen;
ssize_t rbytes;
uchar_t *buf;
if (pctx->enable_archive_sort) {
member_entry_t *mem1, *mem2;
@ -170,10 +172,15 @@ read_next(pc_ctx_t *pctx, char *fpath)
srt = srt->next;
}
if (pctx->temp_mmap_len == 0) {
if (lseek(pctx->archive_members_fd, mem1->file_pos, SEEK_SET) == (off_t)-1) {
log_msg(LOG_ERR, 1, "Error seeking in archive members file.");
return (-1);
}
} else {
pctx->temp_file_pos = mem1->file_pos;
}
srt1->pos++;
if (srt1->pos > srt1->max) {
if (srt1 == pctx->archive_sort_buf) {
@ -185,6 +192,57 @@ read_next(pc_ctx_t *pctx, char *fpath)
}
}
}
/*
* Mmap handling. If requested entry is in current mmap region read it. Otherwise attempt
* new mmap.
*/
if (pctx->temp_mmap_len > 0) {
int retried;
if (pctx->temp_file_pos < pctx->temp_mmap_pos ||
pctx->temp_file_pos - pctx->temp_mmap_pos > pctx->temp_mmap_len ||
pctx->temp_mmap_len - (pctx->temp_file_pos - pctx->temp_mmap_pos) < 3) {
uint32_t adj;
do_mmap:
munmap(pctx->temp_mmap_buf, pctx->temp_mmap_len);
adj = pctx->temp_file_pos % pctx->pagesize;
pctx->temp_mmap_pos = pctx->temp_file_pos - adj;
pctx->temp_mmap_len = pctx->archive_temp_size - pctx->temp_file_pos;
if (pctx->temp_mmap_len > TEMP_MMAP_SIZE)
pctx->temp_mmap_len = TEMP_MMAP_SIZE;
pctx->temp_mmap_buf = mmap(NULL, pctx->temp_mmap_len, PROT_READ,
MAP_SHARED, pctx->archive_members_fd, pctx->temp_mmap_pos);
if (pctx->temp_mmap_buf == NULL) {
log_msg(LOG_ERR, 1, "Error mmap-ing archive members file.");
return (-1);
}
}
retried = 0;
buf = pctx->temp_mmap_buf + (pctx->temp_file_pos - pctx->temp_mmap_pos);
namelen = U32_P(buf);
pctx->temp_file_pos += 2;
if (pctx->temp_mmap_len - (pctx->temp_file_pos - pctx->temp_mmap_pos) < namelen) {
if (!retried) {
pctx->temp_file_pos -= 2;
retried = 1;
goto do_mmap;
} else {
log_msg(LOG_ERR, 0, "Unable to mmap after retry.");
return (-1);
}
}
buf = pctx->temp_mmap_buf + (pctx->temp_file_pos - pctx->temp_mmap_pos);
memcpy(fpath, buf, namelen);
fpath[namelen] = '\0';
pctx->temp_file_pos += namelen;
return (namelen);
}
if ((rbytes = Read(pctx->archive_members_fd, &namelen, sizeof(namelen))) != 0) {
if (rbytes < 2) {
log_msg(LOG_ERR, 1, "Error reading archive members file.");
@ -428,6 +486,7 @@ setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
return (-1);
}
a_state.bufpos = 0;
a_state.pathlist_size += wrtn;
}
pctx->archive_size += a_state.arc_size;
pctx->archive_members_count += a_state.fcount;
@ -440,6 +499,7 @@ setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
log_msg(LOG_INFO, 0, "Sorting ...");
a_state.srt->max = a_state.srt_pos - 1;
qsort(a_state.srt->members, a_state.srt_pos, sizeof (member_entry_t), compare_members);
pctx->archive_temp_size = a_state.pathlist_size;
}
pthread_mutex_unlock(&nftw_mutex);
@ -474,6 +534,14 @@ setup_archiver(pc_ctx_t *pctx, struct stat *sbuf)
archive_write_open_fd(arc, pctx->archive_data_fd);
pctx->archive_ctx = arc;
pctx->archive_members_fd = fd;
pctx->temp_mmap_len = TEMP_MMAP_SIZE;
pctx->temp_mmap_buf = mmap(NULL, pctx->temp_mmap_len, PROT_READ,
MAP_SHARED, pctx->archive_members_fd, 0);
if (pctx->temp_mmap_buf == NULL) {
log_msg(LOG_WARN, 1, "Unable to mmap pathlist file, switching to slower read().");
pctx->temp_mmap_len = 0;
}
pctx->temp_mmap_pos = 0;
return (0);
}
@ -620,9 +688,9 @@ archiver_thread_func(void *dat) {
archive_read_disk_set_symlink_physical(ard);
/*
* Read next path entry from list file. read_next() also handles sorted reading.
* Read next path entry from list file. read_next_path() also handles sorted reading.
*/
while ((rbytes = read_next(pctx, fpath)) != 0) {
while ((rbytes = read_next_path(pctx, fpath)) != 0) {
if (rbytes == -1) break;
archive_entry_copy_sourcepath(entry, fpath);
if (archive_read_disk_entry_from_file(ard, entry, -1, NULL) != ARCHIVE_OK) {
@ -670,6 +738,8 @@ archiver_thread_func(void *dat) {
}
done:
if (pctx->temp_mmap_len > 0)
munmap(pctx->temp_mmap_buf, pctx->temp_mmap_len);
archive_entry_free(entry);
archive_entry_linkresolver_free(resolver);
archive_read_free(ard);

1
pcompress.c
View file

@ -2665,6 +2665,7 @@ create_pc_context(void)
ctx->enable_rabin_split = 1;
ctx->rab_blk_size = -1;
ctx->archive_temp_fd = -1;
ctx->pagesize = sysconf(_SC_PAGE_SIZE);
return (ctx);
}

5
pcompress.h
View file

@ -201,6 +201,7 @@ typedef struct pc_ctx {
int archive_mode;
int verbose;
int enable_archive_sort;
int pagesize;
char archive_members_file[MAXPATHLEN];
int archive_members_fd, archive_data_fd;
uint32_t archive_members_count;
@ -209,6 +210,10 @@ typedef struct pc_ctx {
int uncompfd, compfd;
char archive_temp_file[MAXPATHLEN];
int archive_temp_fd;
uint64_t archive_temp_size;
uchar_t *temp_mmap_buf;
uint64_t temp_mmap_pos, temp_file_pos;
uint64_t temp_mmap_len;
unsigned int chunk_num;
uint64_t largest_chunk, smallest_chunk, avg_chunk;
uint64_t chunksize, archive_size;