Dumb me, forgot do redirect to the list. Sorry for that.
Tulio G. Silva
-------- Original Message --------
Subject: Re: [RFC] Bumping ufs.dirhash_maxmem to a larger value?
Date: Mon, 08 Aug 2005 11:08:49 -0300
From: Tulio Guimarães da Silva <[EMAIL PROTECTED]>
To: Xin LI <[EMAIL PROTECTED]>
References: <[EMAIL PROTECTED]>
<[EMAIL PROTECTED]> <[EMAIL PROTECTED]>
I´m suggesting this without any clue of the amount of work required,
but it´s a suggestion, anyway: maybe it could be dinamically calculated
based on the growth of dirhash usage AND available RAM...
I guess 10% is a reasonable *max* value, but this could also be
disabled with a sysctl or compile time variable, à lá MAX_USERS. Say, if
not set, or set to zero, then it´ll be dynamically calculated. For an
initial value, maybe 2% is enough (the same 2MB for a 128MB machine).
Since customized kernels are very frequent, this should not be an issue.
Of course, the ideal "max percentage" could be obtained from
beta-testing, since it should be by default set for a generic setup.
But, again, I´m just guessing. ;)
Tulio G. Silva
Xin LI wrote:
On Sun, Aug 07, 2005 at 02:57:50PM -0400, Chuck Swiger wrote:
[snip]
On the other hand, I've got several firewall boxes with only 128MB, and
it's not reasonable to simply dedicate up to 64MB (half!) to dirhash
without paying more attention to the amount of physical memory that is
actually available.
Forgot to mention that dirhash_maxmem is the upper limit, not the exact
amount that dirhash must use. If your firewall does not host zillion
of large directories then a bigger default dirhash_maxmem would
essentially a big no-op :-)
How big should dirhash_maxmem be? 5-10% of available RAM, perhaps?
Actually this depends on how many large directories that you actively
access, not only the available RAM. If you access only a little of
small directories, e.g. hosting a database, then dirhash won't help
much. But with a lot of large directories having 1000+ files in most
of them, then raising the dirhash_maxmem will be a great help for
performance.
I think it would be great if we can implement a automatical "suggested
value" of dirhash during bootstrap stage, though, which can be overridden
through sysctl.conf or subsequent sysctl.
Cheers,
_______________________________________________
freebsd-performance@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-performance
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
