On 12/9/10 9:09 PM, Xu, Dongxiao wrote: > Test results are: > > Native: 2.729 secs > Fakeroot: 2.752 secs > Pseudo: 51.814 secs > > We saw pseudo cost about 20 times of seconds than native and fakeroot.
I believe that this is part of the fundamental differences between fakeroot and pseudo. Fakeroot only persists data on shutdown, while pseudo does persistence during the read/writes. What I'm surprised by is that opening/closing the SAME file is so busy. I would have expected the larger overhead to be in multiple file read/writes. > I did a profile when the program is running. From the following table we saw > that a lot of cycles are within sqlite3 operations... > > I am wondering whether this point can be optimized? For example, is it > workable to cache those database operations in memory and finally flush it > into > disk when pseudo exits? Pseudo is using sqlite directly. I did some basic checking, and sqlite has been instructed to run with the following modes: PRAGMA legacy_file_format = OFF PRAGMA journal_mode = PERSIST PRAGMA locking_mode = EXCLUSIVE PRAGMA synchronous = OFF Without doing any further investigation perhaps those modes aren't the best ones to use? Also in prior work I've done with sqlite using transaction cues seemed to also help with performance. It would be interesting to determine where the performance penalties are in this. I'm guessing it's the name resolution... but I'm still surprised at the speed. (There is also an IPC transaction between libpseudo and the pseudo server. From your logs that doesn't appear to be too bad though.) --Mark > It's just a first thought and any suggestion and comment is welcome. > > Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit > mask of 0x00 (No unit mask) count 100000 > samples % image name app name symbol > name > 693127 58.2980 no-vmlinux no-vmlinux > /no-vmlinux > 211108 17.7560 libsqlite3.so.0.8.6 libsqlite3.so.0.8.6 > /usr/lib/libsqlite3.so.0.8.6 > 112269 9.4428 libc-2.10.1.so libc-2.10.1.so > /lib/tls/i686/cmov/libc-2.10.1.so > 16792 1.4124 [vdso] (tgid:28674 range:0xfd0000-0xfd1000) a.out > [vdso] (tgid:28674 range:0xfd0000-0xfd1000) > 15256 1.2832 libpthread-2.10.1.so libpthread-2.10.1.so > pthread_mutex_lock > 13163 1.1071 libpthread-2.10.1.so libpthread-2.10.1.so > __pthread_mutex_unlock_usercnt > 7386 0.6212 libpseudo.so libpseudo.so > pseudo_client_op > 6753 0.5680 libpseudo.so libpseudo.so > pseudo_debug_real > 6680 0.5618 pseudo pseudo > pseudo_server_start > 6663 0.5604 [vdso] (tgid:28676 range:0x8d6000-0x8d7000) pseudo > [vdso] (tgid:28676 range:0x8d6000-0x8d7000) > 5049 0.4247 pseudo pseudo pseudo_op > 4906 0.4126 [vdso] (tgid:28467 range:0xd32000-0xd33000) a.out > [vdso] (tgid:28467 range:0xd32000-0xd33000) > 4427 0.3723 [vdso] (tgid:28607 range:0x5c0000-0x5c1000) a.out > [vdso] (tgid:28607 range:0x5c0000-0x5c1000) > 4391 0.3693 [vdso] (tgid:29027 range:0x6d0000-0x6d1000) a.out > [vdso] (tgid:29027 range:0x6d0000-0x6d1000) > 4188 0.3522 [vdso] (tgid:29172 range:0x41a000-0x41b000) a.out > [vdso] (tgid:29172 range:0x41a000-0x41b000) > 3584 0.3014 [vdso] (tgid:2411 range:0x892000-0x893000) a.out > [vdso] (tgid:2411 range:0x892000-0x893000) > 2985 0.2511 pseudo pseudo > pseudo_debug_real > 2921 0.2457 postgres postgres > /usr/lib/postgresql/8.3/bin/postgres > 2905 0.2443 vim.basic vim.basic > /usr/bin/vim.basic > 2449 0.2060 bash bash /bin/bash > 2439 0.2051 libpseudo.so libpseudo.so fopen > 2163 0.1819 [vdso] (tgid:28609 range:0x3da000-0x3db000) pseudo > [vdso] (tgid:28609 range:0x3da000-0x3db000) > 2096 0.1763 [vdso] (tgid:29029 range:0xfef000-0xff0000) pseudo > [vdso] (tgid:29029 range:0xfef000-0xff0000) > 2086 0.1755 libpseudo.so libpseudo.so > pseudo_append_element > 1917 0.1612 [vdso] (tgid:28469 range:0xe72000-0xe73000) pseudo > [vdso] (tgid:28469 range:0xe72000-0xe73000) > 1835 0.1543 libpseudo.so libpseudo.so wrap_fopen > 1833 0.1542 libpseudo.so libpseudo.so > pseudo_msg_receive > 1819 0.1530 libpseudo.so libpseudo.so __lxstat64 > 1762 0.1482 libpseudo.so libpseudo.so > __i686.get_pc_thunk.bx > > Thanks, > Dongxiao _______________________________________________ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
