ntfs-3g high cpu usage & slow write speed

[Szilárd Páll]

Binary package hint: ntfs-3g

When writing to an NTFS partition a few seconds after starting the operation the CPU usage of the process /sbin/mount.ntfs jumps up (to ~100% on one core) and remains unchanged until the write operation stops. I confirmed this pretty accurately with iotop: when pausing a copying as soon as the buffers get flushed the CPU usage drops to 0.
Also, as soon as the CPU usage of ntfs.mount hits the ~100% the write speed drops to a dreadful few hundred KiB/s.

The above bug is not 100% reproducible, the file written has to be large enough (in my case the initial ~20 MiB/s write speed drops to below 1MiB/s in about 15-20s).

ProblemType: Bug
Architecture: i386
Date: Sat Apr 3 21:06:54 2010
DistroRelease: Ubuntu 9.10
ExecutablePath: /bin/ntfs-3g
Package: ntfs-3g 1:2009.4.4-1ubuntu4
ProcEnviron:

ProcVersionSignature: Ubuntu 2.6.31-20.58-generic
SourcePackage: ntfs-3g
Uname: Linux 2.6.31-20-generic i686

[Mikko Korkalo (keitsi)]

I maybe have the same problem on 10.04.1 LTS

When moving files from NTFS partition to other (on different drive), I got a speed of 13747 bytes per second (13 KBps).
I see 50-90% CPU usage on one of the mount.ntfs processes, and uptime says:
 15:46:09 up 2:28, 2 users, load average: 2.07, 2.06, 1.94

I have Pentium 4 HT 3GHz on the machine, so there should be plenty of processing power.

root@ksrv:~# top|grep mount
 1198 root 20 0 5212 1680 340 R 26 0.7 14:56.43 mount.ntfs
 3778 root 20 0 8268 4596 332 R 7 1.9 3:15.28 mount.ntfs
root@ksrv:~# cat /etc/motd
Linux ksrv 2.6.32-24-generic-pae #43-Ubuntu SMP Thu Sep 16 15:30:27 UTC 2010 i686 GNU/Linux
Ubuntu 10.04.1 LTS
root@ksrv:~# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping : 1
cpu MHz : 2992.845
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pebs bts pni dtes64 monitor ds_cpl cid cx16 xtpr
bogomips : 5985.69
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping : 1
cpu MHz : 2992.845
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 1
initial apicid : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pebs bts pni dtes64 monitor ds_cpl cid cx16 xtpr
bogomips : 5985.41
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:
root@ksrv:~# free
             total used free shared buffers cached
Mem: 242068 238416 3652 0 134556 48004
-/+ buffers/cache: 55856 186212
Swap: 976888 10876 966012

On difference scenarios, I have seen 50 MB+ performance on the drives using ntfs-3g.
It looks like it depends on the files, possibly file size, like said above.

[laulau (olaulau)]

bug still exists on 13.04 amd64.