On Fri, Jul 19, 2013 at 10:17:37AM +0800, Robert Yang wrote: > Let debugfs do sparse copy when src is a sparse file, just like > "cp --sparse=auto" > > * For the > #define IO_BUFSIZE 32*1024 > > This is from coreutils-8.13/src/ioblksize.h (GPL V3): > /* As of Mar 2009, 32KiB is determined to be the minimium > blksize to best minimize system call overhead. > This can be tested with this script with the results > shown for a 1.7GHz pentium-m with 2GB of 400MHz DDR2 RAM: Um.... GNU updated this to 64K a couple of years ago: http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/ioblksize.h;h=1ae93255e7d0ccf0855208c7ae5888209997bf16;hb=HEAD Just for laughs I tried it on a T430 with an i5-3320M and 16G of DDR3-1600 RAM: 1024=3.7 GB/s 2048=7.1 GB/s 4096=8.8 GB/s 8192=14.9 GB/s 16384=14.3 GB/s 32768=13.4 GB/s 65536=15.8 GB/s 131072=20.7 GB/s 262144=16.4 GB/s 524288=15.9 GB/s 1048576=15.8 GB/s 2097152=15.1 GB/s 4194304=11.7 GB/s 8388608=9.9 GB/s 16777216=9.4 GB/s 33554432=9.3 GB/s 67108864=9.3 GB/s 134217728=8.8 GB/s For that matter, a 2010-era i7-950/DDR3-1066 system showed this: 1024=3.4 GB/s 2048=5.6 GB/s 4096=7.8 GB/s 8192=9.5 GB/s 16384=10.8 GB/s 32768=11.4 GB/s 65536=11.6 GB/s 131072=12.2 GB/s 262144=11.9 GB/s 524288=12.3 GB/s 1048576=12.4 GB/s 2097152=12.5 GB/s 4194304=12.5 GB/s 8388608=10.3 GB/s 16777216=8.0 GB/s 33554432=7.6 GB/s 67108864=7.8 GB/s 134217728=7.5 GB/s And for good measure, a cruddy old T2300 Core Duo from 2006 spat out this: 1024=1.1 GB/s 2048=2.1 GB/s 4096=3.6 GB/s 8192=5.0 GB/s 16384=6.3 GB/s 32768=6.5 GB/s 65536=6.6 GB/s 131072=7.0 GB/s 262144=7.1 GB/s 524288=7.1 GB/s 1048576=6.8 GB/s 2097152=4.4 GB/s 4194304=2.3 GB/s 8388608=2.0 GB/s 16777216=2.0 GB/s 33554432=2.0 GB/s 67108864=2.0 GB/s 134217728=1.9 GB/s I suspect you could increase the buffer size to 128K (or possibly even BLKRAGET size?) without much of a problem... > > for i in $(seq 0 10); do > size=$((8*1024**3)) #ensure this is big enough > bs=$((1024*2**$i)) > printf "%7s=" $bs > dd bs=$bs if=/dev/zero of=/dev/null count=$(($size/$bs)) 2>&1 | > sed -n 's/.* \([0-9.]* [GM]B\/s\)/\1/p' > done > > 1024=734 MB/s > 2048=1.3 GB/s > 4096=2.4 GB/s > 8192=3.5 GB/s > 16384=3.9 GB/s > 32768=5.2 GB/s > 65536=5.3 GB/s > 131072=5.5 GB/s > 262144=5.7 GB/s > 524288=5.7 GB/s > 1048576=5.8 GB/s > > Note that this is to minimize system call overhead. > Other values may be appropriate to minimize file system > or disk overhead. For example on my current GNU/Linux system > the readahead setting is 128KiB which was read using: > > file="." > device=$(df -P --local "$file" | tail -n1 | cut -d' ' -f1) > echo $(( $(blockdev --getra $device) * 512 )) > > However there isn't a portable way to get the above. > In the future we could use the above method if available > and default to io_blksize() if not. > */ > enum { IO_BUFSIZE = 32*1024 }; > > Signed-off-by: Robert Yang <liezhi.yang@xxxxxxxxxxxxx> > Acked-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx> > --- > debugfs/debugfs.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 60 insertions(+), 10 deletions(-) > > diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c > index b77d0b5..e443703 100644 > --- a/debugfs/debugfs.c > +++ b/debugfs/debugfs.c > @@ -37,6 +37,16 @@ extern char *optarg; > #include "../version.h" > #include "jfs_user.h" > > +/* 32KiB is the minimium blksize to best minimize system call overhead. */ > +#ifndef IO_BUFSIZE > +#define IO_BUFSIZE 32*1024 > +#endif > + > +/* Block size for `st_blocks' */ > +#ifndef S_BLKSIZE > +#define S_BLKSIZE 512 > +#endif > + > ss_request_table *extra_cmds; > const char *debug_prog_name; > int sci_idx; > @@ -1571,14 +1581,17 @@ void do_find_free_inode(int argc, char *argv[]) > } > > #ifndef READ_ONLY > -static errcode_t copy_file(int fd, ext2_ino_t newfile) > +static errcode_t copy_file(int fd, ext2_ino_t newfile, int bufsize, > + int make_holes, int *zero_written) > { > ext2_file_t e2_file; > errcode_t retval; > int got; > unsigned int written; > - char buf[8192]; > + char buf[bufsize]; ...well, I guess it could be more of a problem if you put 128K on the stack. --D > char *ptr; > + char *cp; > + int count; > > retval = ext2fs_file_open(current_fs, newfile, > EXT2_FILE_WRITE, &e2_file); > @@ -1594,14 +1607,30 @@ static errcode_t copy_file(int fd, ext2_ino_t newfile) > goto fail; > } > ptr = buf; > + cp = ptr; > + count = got; > while (got > 0) { > - retval = ext2fs_file_write(e2_file, ptr, > - got, &written); > - if (retval) > - goto fail; > - > - got -= written; > - ptr += written; > + if (make_holes) { > + /* Check whether all is zero */ > + while (count-- && *cp++ == 0) > + continue; > + if (count < 0) { > + /* The whole block is zero, make a hole */ > + retval = ext2fs_file_lseek(e2_file, got, EXT2_SEEK_CUR, NULL); > + if (retval) > + goto fail; > + got = 0; > + } > + } > + /* Normal copy */ > + if (got > 0) { > + *zero_written = 0; > + retval = ext2fs_file_write(e2_file, ptr, got, &written); > + if (retval) > + goto fail; > + got -= written; > + ptr += written; > + } > } > } > retval = ext2fs_file_close(e2_file); > @@ -1620,6 +1649,9 @@ void do_write(int argc, char *argv[]) > ext2_ino_t newfile; > errcode_t retval; > struct ext2_inode inode; > + int bufsize = IO_BUFSIZE; > + int make_holes = 0; > + int zero_written = 1; > > if (common_args_process(argc, argv, 3, 3, "write", > "<native file> <new file>", CHECK_FS_RW)) > @@ -1684,9 +1716,27 @@ void do_write(int argc, char *argv[]) > return; > } > if (LINUX_S_ISREG(inode.i_mode)) { > - retval = copy_file(fd, newfile); > + if (statbuf.st_blocks < statbuf.st_size / S_BLKSIZE) { > + make_holes = 1; > + /* > + * Use I/O blocksize as buffer size when > + * copying sparse files. > + */ > + bufsize = statbuf.st_blksize; > + } > + retval = copy_file(fd, newfile, bufsize, make_holes, &zero_written); > if (retval) > com_err("copy_file", retval, 0); > + > + if ((inode.i_flags & EXT4_EXTENTS_FL) && zero_written) { > + /* > + * If no data is copied which indicateds that no write > + * happens, we need to turn off the EXT4_EXTENTS_FL. > + */ > + inode.i_flags &= ~EXT4_EXTENTS_FL; > + if (debugfs_write_inode(newfile, &inode, argv[0])) > + close(fd); > + } > } > close(fd); > } > -- > 1.8.1.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
