* How to feel the real time feature of XFS from userspace
@ 2013-11-09 5:23 harryxiyou
2013-11-09 7:59 ` Jeff Liu
0 siblings, 1 reply; 8+ messages in thread
From: harryxiyou @ 2013-11-09 5:23 UTC (permalink / raw)
To: xfs; +Cc: zwu.kernel
Hi all,
I have format block device with XFS as follows.
root@node2:~# mkfs.xfs -f -r rtdev=/dev/sda3 /dev/sda4
meta-data=/dev/sda4 isize=256 agcount=4, agsize=56122440 blks
= sectsz=512 attr=2, projid32bit=0
data = bsize=4096 blocks=224489757, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal log bsize=4096 blocks=109614, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =/dev/sda3 extsz=4096 blocks=14865657,
rtextents=14865657
And I also write user-space codes as follows.
root@node2:~/test# cat xfs.c
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <xfs/xfs.h>
#include <xfs/xfs_fs.h>
int main(int argc, char **argv) {
int fd;
int xfs_ret = 0;
fd = open("./1", O_RDWR);
if (fd < 0) {
fprintf(stderr, "open error!\n");
return -1;
}
xfs_ret = xfsctl("./1", fd, XFS_IOC_FSGETXATTR, NULL);
return 0;
}
Now, I am wondering how to feel the real time feature of XFS from userspace?
Could anyone please give me some suggestions? Thanks in advance.
--
Thanks
Weiwei Jia (Harry Wei)
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 5:23 How to feel the real time feature of XFS from userspace harryxiyou
@ 2013-11-09 7:59 ` Jeff Liu
2013-11-09 9:24 ` harryxiyou
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Jeff Liu @ 2013-11-09 7:59 UTC (permalink / raw)
To: harryxiyou; +Cc: zwu.kernel, xfs
On 11/09/2013 01:23 PM, harryxiyou wrote:
> Hi all,
>
> I have format block device with XFS as follows.
>
> root@node2:~# mkfs.xfs -f -r rtdev=/dev/sda3 /dev/sda4
>
> meta-data=/dev/sda4 isize=256 agcount=4, agsize=56122440 blks
>
> = sectsz=512 attr=2, projid32bit=0
>
> data = bsize=4096 blocks=224489757, imaxpct=25
>
> = sunit=0 swidth=0 blks
>
> naming =version 2 bsize=4096 ascii-ci=0
>
> log =internal log bsize=4096 blocks=109614, version=2
>
> = sectsz=512 sunit=0 blks, lazy-count=1
>
> realtime =/dev/sda3 extsz=4096 blocks=14865657,
> rtextents=14865657
>
>
> And I also write user-space codes as follows.
>
> root@node2:~/test# cat xfs.c
> #include <stdio.h>
> #include <unistd.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <xfs/xfs.h>
> #include <xfs/xfs_fs.h>
>
> int main(int argc, char **argv) {
> int fd;
> int xfs_ret = 0;
>
> fd = open("./1", O_RDWR);
> if (fd < 0) {
> fprintf(stderr, "open error!\n");
> return -1;
> }
> xfs_ret = xfsctl("./1", fd, XFS_IOC_FSGETXATTR, NULL);
>
> return 0;
> }
>
>
> Now, I am wondering how to feel the real time feature of XFS from userspace?
> Could anyone please give me some suggestions? Thanks in advance.
Mount your realtime device at first:
mount -o rtdev=/dev/sda3 /dev/sda4 /mount_point
Then you need to mark the attribute bit set with XFS_XFLAG_REALTIME via xfsctl(3)
after file creation before writing any data to the file, hence your demo code
would looks like:
struct fsxattr attr;
attr.fsx_xflags |= XFS_XFLAG_REALTIME;
xfs_ret = xfsctl(target_file_path, fd, XFS_IOC_FSSETXATTR, &attr);
...
I would suggest you take a look at the source of xfs_rctp(8) at xfsprogs to get
more info.
BTW, I remember Dave once mentioned that the realtime feature on Linux is not widely
tested and not recommended for production use.
Thanks,
-Jeff
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 7:59 ` Jeff Liu
@ 2013-11-09 9:24 ` harryxiyou
2013-11-09 10:13 ` Jeff Liu
2013-11-09 9:31 ` Stan Hoeppner
2013-11-09 12:04 ` Martin Steigerwald
2 siblings, 1 reply; 8+ messages in thread
From: harryxiyou @ 2013-11-09 9:24 UTC (permalink / raw)
To: Jeff Liu; +Cc: Zhi Yong Wu, xfs
On Sat, Nov 9, 2013 at 3:59 PM, Jeff Liu <jeff.liu@oracle.com> wrote:
Hi Jeff Liu,
Thanks for your reply ;-)
> Mount your realtime device at first:
> mount -o rtdev=/dev/sda3 /dev/sda4 /mount_point
>
> Then you need to mark the attribute bit set with XFS_XFLAG_REALTIME via xfsctl(3)
> after file creation before writing any data to the file, hence your demo code
> would looks like:
>
> struct fsxattr attr;
>
> attr.fsx_xflags |= XFS_XFLAG_REALTIME;
> xfs_ret = xfsctl(target_file_path, fd, XFS_IOC_FSSETXATTR, &attr);
> ...
Yeah, it's right. I have mounted as you said and changed my codes as follows.
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <xfs/xfs.h>
#include <xfs/xfs_fs.h>
#define F_PATH "./rtxfs.txt"
#define EXTSIZE (0x00001000U)
int main(int argc, char **argv) {
int fd;
int ret = 0;
struct fsxattr fsxattr;
fd = open(F_PATH, O_RDWR|O_CREAT, 0666);
if (fd < 0) {
fprintf(stderr, "open error!\n");
return -1;
}
fsxattr.fsx_xflags = XFS_XFLAG_REALTIME;
fsxattr.fsx_extsize = EXTSIZE;
if (xfsctl(F_PATH, fd, XFS_IOC_FSSETXATTR, &fsxattr)) {
fprintf(stderr, "Set XFS attributes error!\n");
ret = -1;
goto out;
}
out:
close(fd);
return ret;
}
>
> I would suggest you take a look at the source of xfs_rctp(8) at xfsprogs to get
> more info.
xfs_rtcp really helps me a lot.
>
> BTW, I remember Dave once mentioned that the realtime feature on Linux is not widely
> tested and not recommended for production use.
>
However, I am wondering, now, I have created a XFS real-time file
named "rtfs.txt" and how I
could do some real-time stuffs on this file, which is different from
other common files.
--
Thanks
Weiwei Jia (Harry Wei)
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 7:59 ` Jeff Liu
2013-11-09 9:24 ` harryxiyou
@ 2013-11-09 9:31 ` Stan Hoeppner
2013-11-09 12:04 ` Martin Steigerwald
2 siblings, 0 replies; 8+ messages in thread
From: Stan Hoeppner @ 2013-11-09 9:31 UTC (permalink / raw)
To: Jeff Liu, harryxiyou; +Cc: zwu.kernel, xfs
On 11/9/2013 1:59 AM, Jeff Liu wrote:
> On 11/09/2013 01:23 PM, harryxiyou wrote:
> BTW, I remember Dave once mentioned that the realtime feature on Linux is not widely
> tested and not recommended for production use.
He's mentioned this fact many times. He's also mentioned the fact that
the name "realtime device" is quite misleading.
--
Stan
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 9:24 ` harryxiyou
@ 2013-11-09 10:13 ` Jeff Liu
2013-11-09 11:44 ` harryxiyou
0 siblings, 1 reply; 8+ messages in thread
From: Jeff Liu @ 2013-11-09 10:13 UTC (permalink / raw)
To: harryxiyou; +Cc: Zhi Yong Wu, xfs
Hi Harry,
On Sat, Nov 9, 2013 at 17: 24 PM, harryxiyou wrote:
> On Sat, Nov 9, 2013 at 3:59 PM, Jeff Liu <jeff.liu@oracle.com> wrote:
>
> Hi Jeff Liu,
>
> Thanks for your reply ;-)
>
>> Mount your realtime device at first:
>> mount -o rtdev=/dev/sda3 /dev/sda4 /mount_point
>>
>> Then you need to mark the attribute bit set with XFS_XFLAG_REALTIME via xfsctl(3)
>> after file creation before writing any data to the file, hence your demo code
>> would looks like:
>>
>> struct fsxattr attr;
>>
>> attr.fsx_xflags |= XFS_XFLAG_REALTIME;
>> xfs_ret = xfsctl(target_file_path, fd, XFS_IOC_FSSETXATTR, &attr);
>> ...
> Yeah, it's right. I have mounted as you said and changed my codes as follows.
>
> #include <stdio.h>
> #include <unistd.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <xfs/xfs.h>
> #include <xfs/xfs_fs.h>
>
> #define F_PATH "./rtxfs.txt"
> #define EXTSIZE (0x00001000U)
>
> int main(int argc, char **argv) {
> int fd;
> int ret = 0;
> struct fsxattr fsxattr;
>
> fd = open(F_PATH, O_RDWR|O_CREAT, 0666);
> if (fd < 0) {
> fprintf(stderr, "open error!\n");
> return -1;
> }
> fsxattr.fsx_xflags = XFS_XFLAG_REALTIME;
> fsxattr.fsx_extsize = EXTSIZE;
> if (xfsctl(F_PATH, fd, XFS_IOC_FSSETXATTR, &fsxattr)) {
> fprintf(stderr, "Set XFS attributes error!\n");
> ret = -1;
> goto out;
> }
> out:
> close(fd);
> return ret;
> }
>
>> I would suggest you take a look at the source of xfs_rctp(8) at xfsprogs to get
>> more info.
> xfs_rtcp really helps me a lot.
>
>> BTW, I remember Dave once mentioned that the realtime feature on Linux is not widely
>> tested and not recommended for production use.
>>
> However, I am wondering, now, I have created a XFS real-time file
> named "rtfs.txt" and how I
> could do some real-time stuffs on this file, which is different from
> other common files.
As this inode has been marked to realtime, the subsequent write via
directIO will allocate
extents via it's specific allocation algorithm rather than the general
approach, and the
extent length is specified with fsx_extsize.
AFAICS, the realtime file data will be allocated on realtime volume
while the metadata will
still be allocated from the data volume.
Thanks,
-Jeff
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 10:13 ` Jeff Liu
@ 2013-11-09 11:44 ` harryxiyou
0 siblings, 0 replies; 8+ messages in thread
From: harryxiyou @ 2013-11-09 11:44 UTC (permalink / raw)
To: Jeff Liu; +Cc: Zhi Yong Wu, xfs
On Sat, Nov 9, 2013 at 6:13 PM, Jeff Liu <jeff.liu@oracle.com> wrote:
> Hi Harry,
Hi Jeff,
> As this inode has been marked to realtime, the subsequent write via
> directIO will allocate
> extents via it's specific allocation algorithm rather than the general
> approach, and the
> extent length is specified with fsx_extsize.
> AFAICS, the realtime file data will be allocated on realtime volume
> while the metadata will
> still be allocated from the data volume.
>
I see. However, I think current real-time feature of XFS should be enhanced
and could write/read specific data during specific time interval. I have no
exact ideas about this. I would do if I could. Anyway, thanks for your replies.
--
Thanks
Weiwei Jia (Harry Wei)
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 7:59 ` Jeff Liu
2013-11-09 9:24 ` harryxiyou
2013-11-09 9:31 ` Stan Hoeppner
@ 2013-11-09 12:04 ` Martin Steigerwald
2013-11-09 18:24 ` Emmanuel Florac
2 siblings, 1 reply; 8+ messages in thread
From: Martin Steigerwald @ 2013-11-09 12:04 UTC (permalink / raw)
To: xfs
Am Samstag, 9. November 2013, 15:59:37 schrieb Jeff Liu:
> On 11/09/2013 01:23 PM, harryxiyou wrote:
> > Hi all,
> >
> > I have format block device with XFS as follows.
> >
> > root@node2:~# mkfs.xfs -f -r rtdev=/dev/sda3 /dev/sda4
> >
> > meta-data=/dev/sda4 isize=256 agcount=4, agsize=56122440
> > blks>
> > = sectsz=512 attr=2, projid32bit=0
> >
> > data = bsize=4096 blocks=224489757, imaxpct=25
> >
> > = sunit=0 swidth=0 blks
> >
> > naming =version 2 bsize=4096 ascii-ci=0
> >
> > log =internal log bsize=4096 blocks=109614, version=2
> >
> > = sectsz=512 sunit=0 blks, lazy-count=1
> >
> > realtime =/dev/sda3 extsz=4096 blocks=14865657,
> > rtextents=14865657
> >
> >
> > And I also write user-space codes as follows.
> >
> > root@node2:~/test# cat xfs.c
> > #include <stdio.h>
> > #include <unistd.h>
> > #include <sys/types.h>
> > #include <sys/stat.h>
> > #include <fcntl.h>
> > #include <xfs/xfs.h>
> > #include <xfs/xfs_fs.h>
> >
> > int main(int argc, char **argv) {
> > int fd;
> > int xfs_ret = 0;
> >
> > fd = open("./1", O_RDWR);
> > if (fd < 0) {
> > fprintf(stderr, "open error!\n");
> > return -1;
> > }
> > xfs_ret = xfsctl("./1", fd, XFS_IOC_FSGETXATTR, NULL);
> >
> > return 0;
> > }
> >
> >
> > Now, I am wondering how to feel the real time feature of XFS from
> > userspace? Could anyone please give me some suggestions? Thanks in
> > advance.
>
> Mount your realtime device at first:
> mount -o rtdev=/dev/sda3 /dev/sda4 /mount_point
>
> Then you need to mark the attribute bit set with XFS_XFLAG_REALTIME via
> xfsctl(3) after file creation before writing any data to the file, hence
> your demo code would looks like:
>
> struct fsxattr attr;
>
> attr.fsx_xflags |= XFS_XFLAG_REALTIME;
> xfs_ret = xfsctl(target_file_path, fd, XFS_IOC_FSSETXATTR, &attr);
> ...
>
> I would suggest you take a look at the source of xfs_rctp(8) at xfsprogs to
> get more info.
>
> BTW, I remember Dave once mentioned that the realtime feature on Linux is
> not widely tested and not recommended for production use.
Well, this sounds scary, except from xfs_rtcp(8):
CAVEATS
Currently, realtime partitions are not supported
under the Linux version of XFS, and use of a real‐
time partition WILL CAUSE CORRUPTION on the data
partition. As such, this command is made available
for curious DEVELOPERS ONLY at this point in time.
Especially the corruption part of it.
Whats the current state? Would be interested to know it due to the Linux
Performance Analysis & Tuning courses I hold.
Ciao,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: How to feel the real time feature of XFS from userspace
2013-11-09 12:04 ` Martin Steigerwald
@ 2013-11-09 18:24 ` Emmanuel Florac
0 siblings, 0 replies; 8+ messages in thread
From: Emmanuel Florac @ 2013-11-09 18:24 UTC (permalink / raw)
To: Martin Steigerwald; +Cc: xfs
Le Sat, 09 Nov 2013 13:04:54 +0100 vous écriviez:
> Especially the corruption part of it.
>
> Whats the current state? Would be interested to know it due to the
> Linux Performance Analysis & Tuning courses I hold.
My general feeling is that the RT part is there to ensure
back-compatibility with RT devices coming from Irix, and that's about
it: mount your old Irix drive and get the data off it.
--
------------------------------------------------------------------------
Emmanuel Florac | Direction technique
| Intellique
| <eflorac@intellique.com>
| +33 1 78 94 84 02
------------------------------------------------------------------------
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xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
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2013-11-09 5:23 How to feel the real time feature of XFS from userspace harryxiyou
2013-11-09 7:59 ` Jeff Liu
2013-11-09 9:24 ` harryxiyou
2013-11-09 10:13 ` Jeff Liu
2013-11-09 11:44 ` harryxiyou
2013-11-09 9:31 ` Stan Hoeppner
2013-11-09 12:04 ` Martin Steigerwald
2013-11-09 18:24 ` Emmanuel Florac
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