[Samba] Samba 4 slow write

[Jones Syue]

For clear:​
​


> ​
> Case A) samba-3.6.25 without modification,​
> ​% time     seconds  usecs/call     calls    errors syscall
> ------ ----------- ----------- --------- --------- ----------------
>  57.88    0.165190           0    504915           poll
>  15.10    0.043100           1     80000           pwrite64
>  12.69    0.036217           0    835020           readv
>   6.15    0.017556           0   1539769           gettimeofday
>   4.07    0.011628           0    165038           writev
>   1.20    0.003428           0    421171         2 stat64
>   1.13    0.003222           0    432338           fcntl64
>   0.75    0.002147           0    251161    140043 getxattr
>   0.29    0.000830           0      5015           close
>   0.23    0.000657           0     10000           ftruncate64
>   0.18    0.000508           0     25001           setxattr
>   0.14    0.000410           0     15000           SYS_320
>   0.07    0.000197           0     30023           fstat64
>   0.06    0.000179           0     30005           clock_gettime
>   0.04    0.000117           0      5015           open
>   0.01    0.000036           0      5000           flock
>   0.00    0.000000           0         1           restart_syscall
>   0.00    0.000000           0         2           read
>   0.00    0.000000           0         3           time
>   0.00    0.000000           0        10           lseek
>   0.00    0.000000           0         4           alarm
>   0.00    0.000000           0         3           brk
>   0.00    0.000000           0         1           ioctl
>   0.00    0.000000           0         4           umask
>   0.00    0.000000           0         2           dup2
>   0.00    0.000000           0         3           munmap
>   0.00    0.000000           0         1           fchmod
>   0.00    0.000000           0         4           _llseek
>   0.00    0.000000           0         4           rt_sigaction
>   0.00    0.000000           0         3           mmap2
>   0.00    0.000000           0         2         2 lstat64
>   0.00    0.000000           0        46           geteuid32
>   0.00    0.000000           0        41           getegid32
>   0.00    0.000000           0        19           setreuid32
>   0.00    0.000000           0        19           setregid32
>   0.00    0.000000           0         5           getgroups32
>   0.00    0.000000           0        14           setgroups32
>   0.00    0.000000           0        54           getdents64
> ------ ----------- ----------- --------- --------- ----------------
> 100.00    0.285422               4354716    140047 total
>
> ​


> ​
> Case B) Remove cache lookup from samba-3.6.25,​
> % time     seconds  usecs/call     calls    errors syscall
> ------ ----------- ----------- --------- --------- ----------------
>  57.39    0.275347           1    510297           poll
>  10.68    0.051248           1     80000           pwrite64
>   8.63    0.041410           0    840458           readv
>   4.26    0.020430           0   1555919           gettimeofday
>   3.53    0.016950           0   2513576           fcntl64
>   2.96    0.014199           0    165051           writev
>   1.42    0.006830           0   1520391           geteuid32
>   1.38    0.006627           0   1520387           getegid32
>   0.99    0.004772           0    165850           close
>   0.97    0.004667           0    421195         1 stat64
>   0.83    0.003990           0    640165           setreuid32
>   0.74    0.003569           0    165050           open
>   0.70    0.003370           0    640165           setregid32
>   0.64    0.003071           0    251161    140043 getxattr
>   0.63    0.003002           0    480123           setgroups32
>   0.51    0.002443           0     80019           fchmod
>   0.47    0.002242           0    160039           munmap
>   0.45    0.002182           0    160038    160038 lstat64
>   0.40    0.001905           0    320076           alarm
>   0.38    0.001800           0    400095           getgroups32
>   0.36    0.001727           0    320076           rt_sigaction
>   0.34    0.001634           0     10000           ftruncate64
>   0.33    0.001595           0    160039           mmap2
>   0.27    0.001287           0     80020           read
>   0.20    0.000963           0    190058           fstat64
>   0.17    0.000814           0    160040           _llseek
>   0.16    0.000786           0     25001           setxattr
>   0.09    0.000423           0     15000           SYS_320
>   0.05    0.000220           4        54           getdents64
>   0.04    0.000214           0     30004           clock_gettime
>   0.01    0.000038           0       800       800 connect
>   0.01    0.000032           0      5000           flock
>   0.00    0.000008           0       800           socket
>   0.00    0.000000           0         1           restart_syscall
>   0.00    0.000000           0         1           chdir
>   0.00    0.000000           0        13           time
>   0.00    0.000000           0        10           lseek
>   0.00    0.000000           0         1           ioctl
>   0.00    0.000000           0         2           umask
>   0.00    0.000000           0         1           dup2
> ------ ----------- ----------- --------- --------- ----------------
> 100.00    0.479795              13586976    300882 total
>

​
​
​
--
Regards,
Jones Syue | 薛懷宗
*QNAP* Systems,Inc. <http://www.qnap.com/>​
​