So you think if I try to write a 1 gig file, it will write enough to
fill up the buffers, then wait while the sync'er writes out a few blocks
every second, free up some buffers, then write some more?
Take a look at vfs_bio::getnewbuf() on *BSD and you will see that when
it can't get a
Curtis Faith [EMAIL PROTECTED] writes:
Do you not think this is a potential performance problem to be explored?
I agree that there's a problem if the kernel runs short of buffer space.
I am not sure whether that's really an issue in practical situations,
nor whether we can do much about it at
Bruce,
Is there remarks along these lines in the performance turning section of
the docs? Based on what's coming out of this it would seem that
stressing the importance of leaving a notable (rule of thumb here?)
amount for general OS/kernel needs is pretty important.
Greg
On Tue, 2002-10-08
On Sun, 2002-10-06 at 11:46, Tom Lane wrote:
I can't personally get excited about something that only helps if your
server is starved for RAM --- who runs servers that aren't fat on RAM
anymore? But give it a shot if you like. Perhaps your analysis is
pessimistic.
snipped I don't
Curtis Faith wrote:
Good points.
Now for some surprising news (at least it surprised me).
I researched the file system source on my system (FreeBSD 4.6) and found
that the behavior was optimized for non-database access to eliminate
unnecessary writes when temp files are created and
This is the trickle syncer. It prevents bursts of disk activity every
30 seconds. It is for non-fsync writes, of course, and I assume if the
kernel buffers get low, it starts to flush faster.
AFAICT, the syncer only speeds up when virtual memory paging fills the
buffers past
a threshold and
On Mon, 2002-10-07 at 15:28, Bruce Momjian wrote:
This is the trickle syncer. It prevents bursts of disk activity every
30 seconds. It is for non-fsync writes, of course, and I assume if the
kernel buffers get low, it starts to flush faster.
Doesn't this also increase the likelihood that
Greg Copeland [EMAIL PROTECTED] writes:
Doesn't this also increase the likelihood that people will be
running in a buffer-poor environment more frequently that I
previously asserted, especially in very heavily I/O bound
systems? Unless I'm mistaken, that opens the door for a
general
Greg Copeland [EMAIL PROTECTED] writes:
Doesn't this also increase the likelihood that people will be running in
a buffer-poor environment more frequently that I previously asserted,
especially in very heavily I/O bound systems? Unless I'm mistaken, that
opens the door for a general case of
Curtis Faith wrote:
This is the trickle syncer. It prevents bursts of disk activity every
30 seconds. It is for non-fsync writes, of course, and I assume if the
kernel buffers get low, it starts to flush faster.
AFAICT, the syncer only speeds up when virtual memory paging fills the
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