On Sat, 2007-01-13 at 00:03 +0300, Michael Tokarev wrote: [snip] > And sure thing, withOUT O_DIRECT, the whole system is almost dead under this > load - because everything is thrown away from the cache, even caches of /bin > /usr/bin etc... ;) (For that, fadvise() seems to help a bit, but not alot).
One thing that I've been using, and seems to work well, is a customized
version of the readahead program several distros use during boot up.
Mine starts off doing:
mlockall(MCL_CURRENT|MCL_FUTURE);
...yadda, yadda...
and for each file listed:
...open, stat stuff...
if( NULL == mmap(
NULL, stat_buf.st_size,
PROT_READ, MAP_SHARED|MAP_LOCKED|MAP_POPULATE,
fd, 0)
) {
fprintf(stderr, "'%s' ", file);
perror("mmap");
}
...more stuff...
and then ends with:
pause();
and it sits there forever.
As far as I can tell, this makes the program and library code stay in
RAM. At least, after a drop_caches nautilus doesn't load 12 MB off
disk, it just starts. It has to be reloaded after software updates and
after prelinking. I find the 250 MB used to be worthwhile, even if its
kinda Windowsey.
Something like that could keep your system responsive no matter what the
disk cache is doing otherwise.
--
Zan Lynx <[EMAIL PROTECTED]>
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