Good tips. I have been testing the performance difference of
system-calls, library routines, ipc implementations between Solaris
and Linux. This is one of the test codes I quickly put together to
show the difference. I'll keep your options on the table and suggest
soon as we get to this point.
many thanks.
senthil
On 7/1/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> Your welcome. If the value you are incrementing is unique to each thread
> you
> can try forcing them onto their own cache line
>
> int value[64];
> #define VALUE_1 0
> #define VALUE_2 16
> #define VALUE_3 32
> #define VALUE_4 48
>
> Where value would be one location for the thread. This will remove
> potential cache thrashing going on.
> If you are using one value then you could try placing them together on a
> cache line (take the single miss for the lock and update).
>
> struct data {
> mutex lock;
> int count;
> int pad_to_64[14];
> };
>
> There are games that you need to play with the compiler/loader to get these
> lined up on their own
> cache line, what that game is depends on the code.
>
> Dave V
>
>
> senthil ramanujam wrote:
>
> > Hi Dave,
> >
> > hmmm, I was kind of expecting this answer. Thanks for your analysis.
> >
> > senthil
> >
> > On 7/1/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> >
> >
> > > Ok, this pretty much verifies what I thought. In the short, by running
> > > truss you have
> > > slowed things down enough in the application to significantly remove
> the
> > > lock contention
> > > on the program's mutex. This is one of those performance items that
> > > appears to be contradictory
> > > on the surface.
> > >
> > > A bit more on this now:
> > >
> > > Your program has a very tight loop, you acquire the lock, increment a
> > > variable and drop the
> > > lock. There is a whole slew of atomic_* operations that essentially
> does
> > > the same thing, just
> > > more efficient (if they can be used depends on the case).
> > > By being a tight loop as it is, during the operation of the program
> without
> > > truss it ends up having
> > > the threads queuing up on each other in attempt to acquire the lock.
> When
> > > we miss on a lock because
> > > it is owned by another thread we end up going into a totally different
> set
> > > of lock routines which is
> > > expensive. By running truss what you have done is slowed things down
> > > enough to reduce the
> > > lock contention being seen on the mutex in your program and the
> likeliness
> > > of entering the "slow" lock
> > > path. If you were to add work before or after the mutex operation you
> will
> > > see the same effect, and probably
> > > even to a greater degree.
> > > Hope this helps.
> > >
> > >
> > > Dave Valin
> > >
> > > senthil ramanujam wrote:
> > >
> > >
> > >
> > > > Hi Dave,
> > > >
> > > > Here is the plockstat data for both the cases. Let me know if you like
> > > > to see more details.
> > > >
> > > > Looking forward to hear your comments.
> > > >
> > > > thanks.
> > > >
> > > > senthil
> > > >
> > > >
> > > > $ plockstat -A mutex_ops -w4 -r10
> > > > number of threads:4, run-time (in seconds)=10
> > > > Thread 2: total ops: 456161, ops/second: 45616
> > > > Thread 0: total ops: 452104, ops/second: 45210
> > > > Thread 1: total ops: 167338, ops/second: 16733
> > > > Thread 3: total ops: 174826, ops/second: 17482
> > > > plockstat: pid 13497 has exited
> > > >
> > > > Mutex hold
> > > >
> > > > Count nsec Lock Caller
> > > >
> > > >
> > > >
> > >
> -------------------------------------------------------------------------------
> > >
> > >
> > > > 1248577 1639 mutex_ops`worker_mutex mutex_ops`do_run+0x1b2
> > > > 1851 1960 mutex_ops`worker_mutex mutex_ops`do_run+0x1b2
> > > > 3 104789 mutex_ops`_iob+0xa8 mutex_ops`do_run+0x25a
> > > > 1 82008 libc.so.1`_uberdata+0xfc0 0x400e16
> > > > 1 42599 libc.so.1`_first_link_lock libc.so.1`_exithandle+0x3b
> > > > 1 39967 libc.so.1`_uberdata+0x60 LM1`ld.so.1`rt_thr_init+0x29
> > > > 4 9374 libc.so.1`_uberdata+0x1040 libc.so.1`_lwp_start
> > > > 4 8402 libc.so.1`_uberdata+0x40
> libc.so.1`pthread_create+0x135
> > > > 1 32844 mutex_ops`_iob+0x28 libc.so.1`_exithandle+0x3b
> > > > 3 9736 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > 4 6343 libc.so.1`_uberdata mutex_ops`main+0x2e7
> > > > 1 25319 mutex_ops`_iob+0xa8 mutex_ops`do_run+0x25a
> > > > 4 6162 libc.so.1`_uberdata mutex_ops`main+0x22e
> > > > 4 4369 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > 2 6982 mutex_ops`worker_mutex mutex_ops`do_run+0xea
> > > > 6 1524 libc.so.1`_uberdata+0xd40 libc.so.1`exit+0x11
> > > > 1 8422 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > 4 1934 libc.so.1`_uberdata+0x1040 libc.so.1`_thrp_unwind+0x5e
> > > > 1 7646 0xfffffd7fff220100
> libc.so.1`_thr_exit_common+0x9c
> > > > 2 3517 mutex_ops`worker_mutex mutex_ops`do_run+0xea
> > > > 1 6603 libc.so.1`_uberdata+0xd40 libc.so.1`libc_init+0x2c6
> > > > 4 1516 libc.so.1`_uberdata+0x1000 libc.so.1`_thrp_unwind+0x5e
> > > > 1 6029 0xfffffd7fff220080
> libc.so.1`pthread_create+0x135
> > > > 1 5789 0xfffffd7fff220080
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 4387 0xfffffd7fff2200c0
> libc.so.1`pthread_create+0x135
> > > > 3 1447 libc.so.1`_uberdata+0xe80 libc.so.1`find_stack+0x18a
> > > > 3 1396 libc.so.1`_uberdata libc.so.1`_thrp_create+0x531
> > > > 1 4078 0xfffffd7fff220100
> libc.so.1`pthread_create+0x135
> > > > 3 1309 libc.so.1`_uberdata
> libc.so.1`pthread_create+0xfe
> > > > 1 3900 0xfffffd7fff220140
> libc.so.1`pthread_create+0x135
> > > > 1 3811 0xfffffd7fff2200c0
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 3436 0xfffffd7fff220140
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 2827 0xfffffd7fff220080
> libc.so.1`pthread_create+0xfe
> > > > 2 1367 libc.so.1`_uberdata+0xe40 libc.so.1`_thrp_unwind+0x5e
> > > > 1 2369 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > > 1 2341 mutex_ops`worker_mutex mutex_ops`do_run+0x1b2
> > > > 1 2311 libc.so.1`_uberdata+0x1040 LM1`ld.so.1`rt_thr_init+0x29
> > > > 1 2056 0xfffffd7fff220100 mutex_ops`main+0x2e7
> > > > 1 1951 0xfffffd7fff2200c0 mutex_ops`main+0x2e7
> > > > 1 1863 0xfffffd7fff220140 mutex_ops`main+0x2e7
> > > > 1 1803 0xfffffd7fff220140
> libc.so.1`pthread_create+0xfe
> > > > 1 1794 libc.so.1`_uberdata mutex_ops`main+0x22e
> > > > 1 1782 0xfffffd7fff220100
> libc.so.1`pthread_create+0xfe
> > > > 1 1671 0xfffffd7fff2200c0
> libc.so.1`pthread_create+0xfe
> > > > 1 1622 mutex_ops`_iob+0xa8 libc.so.1`_exithandle+0x3b
> > > > 1 1510 0xfffffd7fff220080 mutex_ops`main+0x2e7
> > > > 1 1508 libc.so.1`_uberdata+0xe80 libc.so.1`_thrp_create+0x531
> > > > 1 1506 libc.so.1`_uberdata+0xd40 0x400dbb
> > > > 1 1495 libc.so.1`_uberdata+0xfc0 0x400dbb
> > > > 1 1446 libc.so.1`_uberdata+0xfc0
> libc.so.1`pthread_create+0xfe
> > > > 1 1398 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > > 1 1389 libc.so.1`_uberdata
> libc.so.1`pthread_create+0xfe
> > > > 1 1370 libc.so.1`_uberdata+0xfc0
> libc.so.1`pthread_create+0xfe
> > > > 1 1347 libc.so.1`_uberdata+0xd40 0x400dc7
> > > > 1 1310 libc.so.1`_uberdata+0xfc0 0x400dc7
> > > > 1 1194 libc.so.1`_uberdata+0xfc0
> libc.so.1`pthread_create+0xfe
> > > > 1 1177 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > >
> > > > Mutex block
> > > >
> > > > Count nsec Lock Caller
> > > >
> > > >
> > > >
> > >
> -------------------------------------------------------------------------------
> > >
> > >
> > > > 866 21921703 mutex_ops`worker_mutex mutex_ops`do_run+0x150
> > > > 692495 8328 mutex_ops`worker_mutex mutex_ops`do_run+0x150
> > > > 2 11086954 mutex_ops`worker_mutex mutex_ops`do_run+0x94
> > > > 3 219879 mutex_ops`_iob+0xa8 libc.so.1`_flockget+0x1a
> > > > 1 12013 libc.so.1`_uberdata mutex_ops`main+0x2e7
> > > > 1 2094 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > << trusss + mutex >>
> > > > $ plockstat -A truss -fc mutex_ops -w4 -r10
> > > > number of threads:4, run-time (in seconds)=10
> > > > Thread 2: total ops: 17918909, ops/second: 1791890
> > > > Thread 0: total ops: 18518051, ops/second: 1851805
> > > > Thread 1: total ops: 18280090, ops/second: 1828009
> > > > Thread 3: total ops: 18889775, ops/second: 1888977
> > > >
> > > > syscall seconds calls errors
> > > > _exit .000 1
> > > > write .000 5
> > > > open .000 3 1
> > > > close .000 2
> > > > stat .000 10 7
> > > > getpid .000 1
> > > > fstat .000 1
> > > > ioctl .000 1
> > > > execve .000 1
> > > > lwp_park .634 94191
> > > > lwp_unpark .501 94191
> > > > sigaction .000 1
> > > > getcontext .000 1
> > > > setustack .000 5
> > > > mmap .000 16
> > > > munmap .000 2
> > > > getrlimit .000 1
> > > > memcntl .000 1
> > > > sysconfig .000 2
> > > > yield .082 12845
> > > > lwp_create .000 4
> > > > lwp_exit .000 4
> > > > lwp_continue .000 4
> > > > lwp_sigmask .000 4
> > > > lwp_private .000 1
> > > > lwp_wait .000 4
> > > > lwp_mutex_wakeup .000 10
> > > > nanosleep .000 1
> > > > schedctl .000 5
> > > > resolvepath .000 4
> > > > lwp_mutex_timedlock .000 68
> > > > getcwd .000 1
> > > > -------- ------ ----
> > > > sys totals: 1.219 201391 8
> > > > usr time: 17.809
> > > > elapsed: 10.030
> > > > plockstat: pid 13499 has exited
> > > >
> > > > Mutex hold
> > > >
> > > > Count nsec Lock Caller
> > > >
> > > >
> > > >
> > >
> -------------------------------------------------------------------------------
> > >
> > >
> > > > 257123 8166 truss`truss_lock truss`worker_thread+0x3a7
> > > > 145651 11250 truss`truss_lock truss`worker_thread+0x3a7
> > > > 201384 1893 truss`count_lock truss`sysexit+0x82d
> > > > 1 2468522 libc.so.1`_uberdata+0x60 libproc.so.1`Pxcreate+0x63
> > > > 1 2447046 libnsl.so.1`_ti_userlock
> > > > libnsl.so.1`_libnsl_parent_atfork+0x10
> > > > 1 2380540 libc.so.1`_uberdata+0xfc0 libc.so.1`fork+0x130
> > > > 1 2364179 libc.so.1`_first_link_lock libc.so.1`fork+0x130
> > > > 1 2356270 libc.so.1`libc_malloc_lock libc.so.1`fork+0x130
> > > > 1 2337553 libc.so.1`_uberdata+0x40 libproc.so.1`Pxcreate+0x63
> > > > 4 52074 0x455478 libproc.so.1`Lgrab+0x234
> > > > 1 144394 libc.so.1`_uberdata+0xfc0 truss`main_thread+0x1e8
> > > > 4 32702 truss`truss_lock truss`worker_thread+0x5d6
> > > > 5 23212 0x455478 libproc.so.1`Lfree+0x3a
> > > > 1 66469 0xfef9e1b0 0xfef06df3
> > > > 1 64668 0xfefa12c0 0xfef67a91
> > > > 32 1858 truss`_iob+0xa8 truss`report+0x223
> > > > 1 58652 0x455478 libproc.so.1`Lgrab+0x234
> > > > 5 11034 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > 32 1583 truss`_iob+0xa8 truss`prtim+0x51
> > > > 32 1547 truss`_iob+0xa8 truss`report+0x25e
> > > > 2 23108 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 32 1412 truss`_iob+0xa8 truss`prtim+0x64
> > > > 1 40708 0xfefa12a0 0xfef021df
> > > > 1 40112 libc.so.1`_uberdata+0x60 LM1`ld.so.1`rt_thr_init+0x29
> > > > 1 34837 libc.so.1`_first_link_lock libc.so.1`_exithandle+0x3b
> > > > 5 6891 truss`truss_lock truss`main_thread+0x116
> > > > 1 34270 0xfef9e5d0 0xfef14052
> > > > 4 8244 libc.so.1`_uberdata+0x40 truss`worker_thread+0xe52
> > > > 1 31319 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 5 6235 libc.so.1`_uberdata truss`main_thread+0x125
> > > > 4 7557 libc.so.1`libc_malloc_lock libproc.so.1`Lgrab+0xd3
> > > > 5 6010 libc.so.1`_uberdata+0x1040 libc.so.1`_lwp_start
> > > > 1 29687 libc.so.1`libc_malloc_lock truss`main+0x4ac
> > > > 1 28272 libc.so.1`mktemp_lock.0 truss`main+0xdb4
> > > > 1 26436 truss`truss_lock truss`worker_thread+0x5d6
> > > > 1 25322 truss`_iob+0xa8 libc.so.1`_exithandle+0x3b
> > > > 1 25197 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 4 6142 libc.so.1`_uberdata truss`worker_thread+0xe34
> > > > 1 21847 libc.so.1`libc_malloc_lock truss`my_calloc+0x18
> > > > 1 19740 libproc.so.1`minfd_lock.0 libproc.so.1`set_minfd+0x46
> > > > 1 17725 0xfffffd7fff060140
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 14834 libc.so.1`libc_malloc_lock truss`free_private+0x44
> > > > 5 2865 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 12900 0xfffffd7fff200080 truss`Xcritical+0x46
> > > > 5 2470 libc.so.1`_uberdata
> > > >
> > > >
> > > libc.so.1`_thr_exit_common+0x9c
> > >
> > >
> > > > 1 12239 libc.so.1`__sbrk_lock
> > > >
> > > >
> > > libc.so.1`_malloc_unlocked+0x10d
> > >
> > >
> > > > 1 12155 0xfef9e1f0 0xfef0703b
> > > > 1 12062 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 6 2004 truss`count_lock truss`worker_thread+0x108a
> > > > 1 11918 libc.so.1`_uberdata+0x40 truss`main_thread+0x1ed
> > > > 5 2347 truss`count_lock truss`worker_thread+0xb09
> > > > 1 11608 0xfef9f708 0xfef26ac9
> > > > 5 2215 libc.so.1`libc_malloc_lock
> > > >
> > > >
> > > libproc.so.1`Lfree_internal+0x67
> > >
> > >
> > > > 1 10685 libc.so.1`update_lock
> libctf.so.1`_libctf_init+0x10
> > > > 1 10092 libc.so.1`_uberdata libproc.so.1`Pxcreate+0x63
> > > > 5 2016 libc.so.1`_uberdata+0x1040 libc.so.1`_thrp_unwind+0x5e
> > > > 1 9656 0x455478 libproc.so.1`Pfree+0x117
> > > > 2 4810 libc.so.1`__sbrk_lock libc.so.1`realloc+0x235
> > > > 5 1871 0xfffffd7fff200080 truss`Xcritical+0x46
> > > > 6 1543 libc.so.1`_uberdata+0xd40 libc.so.1`exit+0x11
> > > > 5 1744 libc.so.1`libc_malloc_lock truss`free_private+0x55
> > > > 5 1738 libc.so.1`_uberdata+0x1000 libc.so.1`_thrp_unwind+0x5e
> > > > 5 1688 libc.so.1`libc_malloc_lock truss`free_private+0x66
> > > > 1 8407 truss`count_lock truss`setup_basetime+0x60
> > > > 1 8252 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 2 4044 libc.so.1`__sbrk_lock libc.so.1`malloc+0x2d
> > > > 1 8072 libc.so.1`libc_malloc_lock libproc.so.1`Lgrab+0x72
> > > > 5 1612 libc.so.1`_uberdata+0x1000 libc.so.1`_thrp_unwind+0x5e
> > > > 1 8046 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 5 1543 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 2 3818 libc.so.1`__sbrk_lock libc.so.1`realloc+0x235
> > > > 4 1897 libc.so.1`_uberdata libc.so.1`thr_create+0x3f
> > > > 1 7516 0xfef9e5d0 0xfef14052
> > > > 5 1497 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 7375 0xfffffd7fff060080 truss`main_thread+0x1ed
> > > > 1 7372 libc.so.1`_uberdata truss`create_thread+0x58
> > > > 1 6977 libc.so.1`_uberdata+0xd40 libc.so.1`libc_init+0x2c6
> > > > 1 6664 0xfefa1f80 0xfef63d56
> > > > 4 1663 libc.so.1`_uberdata+0xe80 libc.so.1`find_stack+0x18a
> > > > 1 6569 0xfffffd7fff060180
> libc.so.1`_thr_exit_common+0x9c
> > > > 2 3186 libc.so.1`__sbrk_lock libc.so.1`malloc+0x2d
> > > > 1 6260 libc.so.1`_uberdata+0x1000 truss`main+0xf8
> > > > 1 5847 libc.so.1`libc_malloc_lock libproc.so.1`Lgrab+0xd3
> > > > 1 5799 libc.so.1`_uberdata+0x60
> > > >
> > > >
> > > libnsl.so.1`_libnsl_lock_init+0x86
> > >
> > >
> > > > 1 5664 0xfffffd7fff060140 truss`worker_thread+0xe52
> > > > 1 5502 0xfefa2240 0xfef734b2
> > > > 4 1338 libc.so.1`_uberdata libc.so.1`_thrp_create+0x531
> > > > 1 5248 0xfffffd7fff0600c0 truss`worker_thread+0xe52
> > > > 1 5204 libc.so.1`__sbrk_lock
> > > >
> > > >
> > > libc.so.1`_malloc_unlocked+0x10d
> > >
> > >
> > > > 1 5141 truss`count_lock truss`per_proc_init+0xe1
> > > > 1 5105 0xfefa10e0 0xfef62237
> > > > 1 4904 0xfefa10e0 0xfef62237
> > > > 3 1613 libc.so.1`libc_malloc_lock truss`free_private+0x44
> > > > 1 4403 libc.so.1`_uberdata+0x140 truss`main+0xbeb
> > > > 1 4245 0xfffffd7fff060100 truss`worker_thread+0xe52
> > > > 1 3702 0xfffffd7fff0600c0
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 3469 truss`_iob+0xa8 truss`report+0x418
> > > > 2 1702 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 3396 0xfffffd7fff060100
> libc.so.1`_thr_exit_common+0x9c
> > > > 2 1641 libc.so.1`_uberdata+0xe40 libc.so.1`_thrp_unwind+0x5e
> > > > 2 1514 truss`_iob+0xa8 truss`report+0x366
> > > > 2 1477 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 2 1369 libc.so.1`libc_malloc_lock truss`sysentry+0x4e7
> > > > 1 2653 0xfffffd7fff060080 libc.so.1`thr_create+0x3f
> > > > 1 2646 libc.so.1`_uberdata+0x140 truss`main+0xbff
> > > > 1 2528 truss`truss_lock truss`main_thread+0x116
> > > > 1 2470 libc.so.1`_uberdata+0x580 truss`main+0x554
> > > > 1 2452 0xfffffd7fff200080 truss`Xcritical+0x46
> > > > 1 2391 0xfffffd7fff060080
> libc.so.1`_thr_exit_common+0x9c
> > > > 1 2223 libc.so.1`_uberdata+0x440 truss`main+0x545
> > > > 1 2219 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 2203 libc.so.1`_uberdata+0x4c0 truss`main+0x518
> > > > 1 2187 libc.so.1`_uberdata+0x500 truss`main+0x527
> > > > 1 2185 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > > 1 2182 0xfefa2280 0xfef73271
> > > > 1 2127 0xfffffd7fff060080 truss`main_thread+0x125
> > > > 1 2113 0xfffffd7fff060180 truss`worker_thread+0xe52
> > > > 1 2090 libc.so.1`_uberdata+0x1040 LM1`ld.so.1`rt_thr_init+0x29
> > > > 1 2082 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 2072 libc.so.1`_uberdata+0x540 truss`main+0x536
> > > > 1 2057 libc.so.1`_uberdata+0x180 truss`main+0xc0e
> > > > 1 2041 libc.so.1`_uberdata+0x1c0 truss`main+0xc31
> > > > 1 2035 0xfffffd7fff060140 truss`main_thread+0x125
> > > > 1 2013 0xfffffd7fff060140 libc.so.1`thr_create+0x3f
> > > > 1 1968 libc.so.1`libc_malloc_lock truss`main+0xdf1
> > > > 1 1961 0xfefa2000 0xfef63d56
> > > > 1 1954 libc.so.1`_uberdata libproc.so.1`Pxcreate+0x63
> > > > 1 1927 0xfffffd7fff0600c0 truss`main_thread+0x125
> > > > 1 1923 libc.so.1`_uberdata+0x180 truss`main+0xc22
> > > > 1 1918 0xfffffd7fff060100 libc.so.1`thr_create+0x3f
> > > > 1 1917 truss`_iob+0xa8 truss`prtim+0x20
> > > > 1 1891 0xfffffd7fff060180 truss`main_thread+0x125
> > > > 1 1890 libc.so.1`_uberdata+0x1c0 truss`main+0x507
> > > > 1 1884 libc.so.1`seed_lk truss`main+0xdb4
> > > > 1 1877 libc.so.1`libc_malloc_lock libproc.so.1`Pfree+0x10f
> > > > 1 1875 libc.so.1`libc_malloc_lock libproc.so.1`Pxcreate+0x52
> > > > 1 1867 libc.so.1`libc_malloc_lock truss`main+0xdb4
> > > > 1 1832 0xfffffd7fff0600c0 libc.so.1`thr_create+0x3f
> > > > 1 1830 0xfffffd7fff060100 truss`main_thread+0x125
> > > > 1 1770 libc.so.1`_uberdata+0xfc0 libc.so.1`thr_create+0x3f
> > > > 1 1765 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 1754 truss`_iob+0x28 libc.so.1`_exithandle+0x3b
> > > > 1 1732 libc.so.1`_uberdata+0xd40 truss`main+0xf8
> > > > 1 1723 libc.so.1`_uberdata+0xd40 truss`_start+0x1b
> > > > 1 1695 truss`_iob+0xa8 truss`report+0x4af
> > > > 1 1681 libc.so.1`_uberdata+0xd40
> > > >
> > > >
> > > libnsl.so.1`_libnsl_lock_init+0x86
> > >
> > >
> > > > 1 1674 libc.so.1`_uberdata+0xe80 libc.so.1`_thrp_create+0x531
> > > > 1 1649 0xfefa1f80 0xfef63d56
> > > > 1 1648 truss`_iob+0xa8 truss`report+0x492
> > > > 1 1647 0xfef9e5d0 0xfef14052
> > > > 1 1642 0xfffffd7fff200080 truss`Xcritical+0x46
> > > > 1 1640 truss`_iob+0xa8 truss`report+0x486
> > > > 1 1637 truss`_iob+0xa8 truss`prtim+0x20
> > > > 1 1624 0xfffffd7fff060180 libc.so.1`thr_create+0x3f
> > > > 1 1616 0xfefa2200 0xfef01d17
> > > > 1 1608 libc.so.1`_uberdata truss`create_thread+0x58
> > > > 1 1608 truss`_iob+0xa8 truss`prtim+0x51
> > > > 1 1547 truss`_iob+0xa8 truss`report+0x53e
> > > > 1 1547 truss`_iob+0xa8 truss`prtim+0x51
> > > > 1 1533 0xfefa2040 0xfef63d56
> > > > 1 1518 0xfefa1f80 0xfef63d56
> > > > 1 1505 libc.so.1`libc_malloc_lock libproc.so.1`Pfree+0x1cf
> > > > 1 1488 0xfefa1f80 0xfef63d56
> > > > 1 1466 truss`_iob+0xa8 truss`prtim+0x51
> > > > 1 1445 libc.so.1`libc_malloc_lock truss`free_private+0x88
> > > > 1 1443 libc.so.1`libc_malloc_lock truss`my_realloc+0x18
> > > > 1 1426 truss`_iob+0xa8 truss`report+0x4cb
> > > > 1 1424 truss`_iob+0xa8 truss`prtim+0x20
> > > > 1 1415 0xfef9e5d0 0xfef14052
> > > > 1 1404 libc.so.1`_uberdata+0xfc0 libc.so.1`thr_create+0x3f
> > > > 1 1397 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > > 1 1378 libc.so.1`_uberdata+0xd40 libc.so.1`_thrp_create+0x370
> > > > 1 1372 libc.so.1`_uberdata libc.so.1`thr_create+0x3f
> > > > 1 1363 libc.so.1`libc_malloc_lock truss`free_private+0x90
> > > > 1 1345 libc.so.1`_uberdata+0xd40 truss`_start+0x27
> > > > 1 1343 0xfefa1f80 0xfef63d56
> > > > 1 1341 libc.so.1`_uberdata+0xfc0 truss`_start+0x1b
> > > > 1 1340 0xfefa2200 0xfef01d17
> > > > 1 1324 0xfefa1f80 0xfef63d56
> > > > 1 1284 libc.so.1`_uberdata+0xfc0 libc.so.1`thr_create+0x3f
> > > > 1 1142 libc.so.1`_uberdata+0xfc0 truss`_start+0x27
> > > >
> > > > Mutex block
> > > >
> > > > Count nsec Lock Caller
> > > >
> > > >
> > > >
> > >
> -------------------------------------------------------------------------------
> > >
> > >
> > > > 124379 34360 truss`truss_lock truss`worker_thread+0x27d
> > > > 88153 2193 truss`truss_lock truss`worker_thread+0x27d
> > > > 3 55924 truss`truss_lock truss`worker_thread+0x5c4
> > > > 1 12080 libc.so.1`libc_malloc_lock libc.so.1`free+0x18
> > > > 1 2286 truss`truss_lock truss`main_thread+0xed
> > > > $
> > > >
> > > > On 7/1/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> > > >
> > > >
> > > >
> > > >
> > > > > Could you please provide lockstat information from plockstat for
> each of
> > > > > these
> > > > > cases. I think I know what you are seeing, but I want data to back
> up
> > > > >
> > > > >
> > > >
> > > the
> > >
> > >
> > > >
> > > > > theory.
> > > > >
> > > > > Thanks
> > > > >
> > > > > Dave Valin
> > > > >
> > > > >
> > > > > senthil ramanujam wrote:
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I am seeing a strange performance behavior with pthread mutex
> > > > > > operations on my Solaris (4-core) system running S10U5.
> > > > > >
> > > > > > The issue is that if the program is run with truss enabled, I am
> > > > > > getting about 3 times more the performance of the run without
> truss
> > > > > > enabled. Strange...right?
> > > > > >
> > > > > > The C program does the following:
> > > > > > - accept 2 parameters [number of concurrent threads(N), and
> run-time]
> > > > > > - create and run N threads simultaneously for <run-time> seconds
> > > > > > - each thread does the following:
> > > > > > - acquires the pthread mutex
> > > > > > - increases the value of it's _own_ long variable by 1
> > > > > > - releases the pthread mutex
> > > > > > - after run-time expires, each thread reports the value of it's
> long
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > variable
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > Note that I did not use any special flags to compile it. Reply
> back to
> > > > > > this email if you like to take a look at the program source code.
> > > > > >
> > > > > > Let's look at the program without truss enabled.
> > > > > >
> > > > > > $ mutex_ops -w4 -r10
> > > > > > number of threads:4, run-time (in seconds)=10
> > > > > > Thread 1: total ops: 4580775, ops/second: 458077
> > > > > > Thread 3: total ops: 3798001, ops/second: 379800
> > > > > > Thread 0: total ops: 4867850, ops/second: 486785
> > > > > > Thread 2: total ops: 4925299, ops/second: 492529
> > > > > > $
> > > > > > <<vmstat 1>>
> > > > > > kthr memory page disk faults
> > > > > >
> > > > > >
> > > > >
> > > >
> > > cpu
> > >
> > >
> > > >
> > > > >
> > > > > > r b w swap free re mf pi po fr de sr s0 s1 -- -- in sy
> cs
> > > > > >
> > > > > >
> > > > >
> > > >
> > > us
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > sy id
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 22 205 0 0 0 0 0 0 0 0 0 7960 16218
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 16155 28
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 2 71
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 19914 41572
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 41568
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 81 3 16
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 1 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 18711 39086
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 38937
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 80 3 17
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 19006 39373
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 39382
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 80 3 17
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 18719 39151
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 39007
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 80 3 16
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 19560 41243
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 40963
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 81 4 16
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 20498 43671
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 43203
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 81 4 16
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 20857 44636
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 44014
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 80 4 15
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 19149 41239
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 40583
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 80 4 16
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121968 14961748 0 0 0 0 0 0 0 0 0 0 0 21019 44189
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 43995
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 81 4 15
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17122372 14962176 7 29 0 0 0 0 0 0 0 0 0 13062 27003
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 26973
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 46 2 52
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17122372 14962176 0 0 0 0 0 0 0 0 0 0 0 461 160
> 274
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 0
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 0 100
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > As you can see above that I am executing the program with 4
> concurrent
> > > > > > threads for 10 seconds. The output shows that each thread has
> acquired
> > > > > > the mutex lock about 400,000 times a second. The vmstat shows that
> the
> > > > > > program used about 80% of usertime, 4%system and ~15% idle. So far
> so
> > > > > > good.
> > > > > >
> > > > > > Now, let's look into program with truss case.
> > > > > >
> > > > > > $ truss -fc mutex_ops -w4 -r10
> > > > > > number of threads:4, run-time (in seconds)=10
> > > > > > Thread 0: total ops: 13419838, ops/second: 1341983
> > > > > > Thread 2: total ops: 13959115, ops/second: 1395911
> > > > > > Thread 1: total ops: 13414291, ops/second: 1341429
> > > > > > Thread 3: total ops: 13535670, ops/second: 1353567
> > > > > >
> > > > > > syscall seconds calls errors
> > > > > > _exit .000 1
> > > > > > write .000 5
> > > > > > open .000 3 1
> > > > > > close .000 2
> > > > > > stat .000 10 7
> > > > > > getpid .000 1
> > > > > > fstat .000 1
> > > > > > ioctl .000 1
> > > > > > execve .000 1
> > > > > > lwp_park .905 106423
> > > > > > lwp_unpark .757 106423
> > > > > > sigaction .000 1
> > > > > > getcontext .000 1
> > > > > > setustack .000 5
> > > > > > mmap .000 16
> > > > > > munmap .000 2
> > > > > > getrlimit .000 1
> > > > > > memcntl .000 1
> > > > > > sysconfig .000 2
> > > > > > yield .182 26004
> > > > > > lwp_create .000 4
> > > > > > lwp_exit .000 4
> > > > > > lwp_continue .000 4
> > > > > > lwp_sigmask .000 4
> > > > > > lwp_private .000 1
> > > > > > lwp_wait .000 4
> > > > > > lwp_mutex_wakeup .000 9
> > > > > > nanosleep .000 1
> > > > > > schedctl .000 5
> > > > > > resolvepath .000 4
> > > > > > lwp_mutex_timedlock .000 32
> > > > > > getcwd .000 1
> > > > > > -------- ------ ----
> > > > > > sys totals: 1.846 238977 8
> > > > > > usr time: 21.363
> > > > > > elapsed: 10.060
> > > > > > $
> > > > > >
> > > > > > <<vmstat 1>>
> > > > > > kthr memory page disk faults
> > > > > >
> > > > > >
> > > > >
> > > >
> > > cpu
> > >
> > >
> > > >
> > > > >
> > > > > > r b w swap free re mf pi po fr de sr s0 s1 -- -- in sy
> cs
> > > > > >
> > > > > >
> > > > >
> > > >
> > > us
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > sy id
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17122372 14962176 0 0 0 0 0 0 0 0 0 0 0 529 262
> 335
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 0
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 0 100
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > 0 0 0 17121240 14960660 153 632 0 0 0 0 0 0 0 0 0 25259 91754
> > > > > > 87992 37 15 48
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 62751
> 178228
> > > > > > 179102 57 33 10
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 56922
> 169565
> > > > > > 168507 59 30 11
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 60935
> 178967
> > > > > > 178535 58 32 10
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 61581
> 180239
> > > > > > 179751 58 32 10
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 61486
> 181664
> > > > > > 180513 58 33 10
> > > > > > 1 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 67941
> 186205
> > > > > > 190703 55 35 10
> > > > > > 0 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 59981
> 175708
> > > > > > 175758 58 32 10
> > > > > > 1 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 60485
> 174557
> > > > > > 175091 58 32 11
> > > > > > 1 0 0 17121104 14960524 0 0 0 0 0 0 0 0 0 0 0 62799
> 178328
> > > > > > 179880 57 32 10
> > > > > > 0 0 0 17122236 14962040 8 17 0 0 0 0 0 0 0 0 0 19483 58122
> > > > > > 58317 19 10 71
> > > > > > 0 0 0 17122236 14962040 0 0 0 0 0 0 0 0 0 0 0 449 160
> 279
> > > > > >
> > > > > >
> > > > >
> > > >
> > > 0
> > >
> > >
> > > >
> > > > >
> > > > > >
> > > > > >
> > > > > 0 100
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > > Can you spot the issue? I used the same parameters(4 concurrent
> > > > > > threads, 10 seconds run-time), but this time *with truss enabled*.
> The
> > > > > > output shows that each thread has acquired the mutex lock about
> > > > > > 1,300,000 times a second. vmstat shows that the program is using a
> lot
> > > > > > more system time than before. However, I don't know how truss can
> > > > > > cause the system time to go up, which ultimately increases the
> > > > > > performance. Am I missing something?
> > > > > >
> > > > > > BTW, I confirmed the mutex locks generated by the program using
> > > > > > dtrace. The values are indeed correct for both the cases.
> > > > > >
> > > > > > Any inputs/comments are appreciated.
> > > > > >
> > > > > > thanks.
> > > > > >
> > > > > > senthil
> > > > > > _______________________________________________
> > > > > > perf-discuss mailing list
> > > > > > [email protected]
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
>
>
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