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
"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
> 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 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
> 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
>
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 cas
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
> 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 a
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
> 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.
>
> I don't
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