Hi,
I did some simple tests for pseudo performance.
I wrote a simple program which is repeatedly calling fopen, fflush, and fclose,
which should be sensitive to pseudo/fakeroot since they trap the system calls.
I run the program on native, fakeroot, and pseudo.
int main()
{
FILE *fp;
int i;
for (i = 0; i < 1000000; i++) {
fp = fopen("/tmp/12321.txt", "w");
fflush(fp);
fclose(fp);
}
return 0;
}
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 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?
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
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