Re: Tuning Question
On Wednesday 25 February 2009 16:36:39 Scott Seekamp wrote: > I did search and it did not return any results. They should really kill the htdig project already ;) > That is helpful, but I was hoping to get an indication of what the > effects of changing this setting and what is the maximum before looking > elsewhere for changes? Your system might be wanting more then the system can offer. It's further explained here: Quoting Mark Tinguely: > Sometimes pv_entry allocation can fail even below the pv_entry_high_water > if there is no more free pages available to allocate for a pv_entry chunk. > Operations (such temp mappings, copies) will not occur if the > pv_entry_high_water (90% if pv_entry_max) has been reached OR a > page is not immediately available for allocation. I don't know what the max is. If you have to increase it a lot, f.e. >500%, then either the default is porely chosen, you demand a lot or your system is doing things it's not supposed to do. I would slowly increase it to insane ammounts. If it never goes away and load of the machine isn't shocking, then this might be a bug. Either way, there aren't too many tools to diagnose this problem. Maybe procstat(8) -v should give some insight. -- Mel Problem with today's modular software: they start with the modules and never get to the software part. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Tuning Question
On Wednesday 25 February 2009 14:09:22 Scott Seekamp wrote: > I didn't want to arbitrarily adjust the settings without understanding > them. I could not find any good information out there on what to adjust > these values to, or what to base them off of. You didn't search the archives of this list. Just answered this like a week ago. -- Mel Problem with today's modular software: they start with the modules and never get to the software part. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Tuning Question
Cy Schubert <[EMAIL PROTECTED]> writes: > Top's output, as is free memory on all O/S's these days, is bogus. It's the > size of the free memory pool which is available for immediate allocation. > Used memory is just as useless. It doesn't matter how much is swapped out, > what matters is how much I/O is being performed to support VM. I know at > work, which is an Oracle ghetto, paging should be kept at a minimum, > especially the SGA. Other apps can afford more. In the case of an average > FreeBSD system it's been guesswork. What I thought you should use top for is tracking the swapping rates. But that's not enough, because the acceptable rates will depend on what else is happening in the system. If the CPU is maxed out anyway (for example), then reducing the swapping will not improve your performance. My general approach to optimization is to identify a problem first. If you can't pin down a performance problem that you want to solve, then you aren't going to be able to prove that any changes fix that problem anyway. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Tuning Question
In message <[EMAIL PROTECTED]>, Lowell Gilbert writes: > Cy Schubert <[EMAIL PROTECTED]> writes: > > > I have a question about tuning FreeBSD systems, specifically in regard to > > memory. At one time on Solaris systems it was recommended to keep scan rate > > > below 200 pages per second. (Today it's 300 pages per second, dependent on > > the amount of memory, class of system.) Are there any recommendations or > > rules of thumb a person can use to determine when a memory upgrade is > > required? My machines are only busy during port builds when the scan rate > > can vary greatly and the page out rate could reach as high as two pages per > > > second during brief periods. What kind of memory and paging metrics should > > I use on FreeBSD systems? > > I'm not convinced that such a simple algorithm makes sense these days. > If the system is normally pretty quiet, then it is unlikely you'll see > any difference from optimizing memory behaviour further. > > I believe that when top(1) gives memory sizes, they are in bytes > rather than pages as the manual indicates. Top's output, as is free memory on all O/S's these days, is bogus. It's the size of the free memory pool which is available for immediate allocation. Used memory is just as useless. It doesn't matter how much is swapped out, what matters is how much I/O is being performed to support VM. I know at work, which is an Oracle ghetto, paging should be kept at a minimum, especially the SGA. Other apps can afford more. In the case of an average FreeBSD system it's been guesswork. I should also mention that even though Sun recommended certain metrics for their systems. In a previous life as an MVS (IBM mainframe) systems programmer, IBM recommended that no more than 5% of system resources should be used for paging, otherwise you're paging too much. I suppose this might be a good paper for someone to write. (As I'm already writing a book, I probably don't have time to research and write yet another subject.) -- Cheers, Cy Schubert <[EMAIL PROTECTED]> FreeBSD UNIX: <[EMAIL PROTECTED]> Web: http://www.FreeBSD.org e**(i*pi)+1=0 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Tuning Question
Cy Schubert <[EMAIL PROTECTED]> writes: > I have a question about tuning FreeBSD systems, specifically in regard to > memory. At one time on Solaris systems it was recommended to keep scan rate > below 200 pages per second. (Today it's 300 pages per second, dependent on > the amount of memory, class of system.) Are there any recommendations or > rules of thumb a person can use to determine when a memory upgrade is > required? My machines are only busy during port builds when the scan rate > can vary greatly and the page out rate could reach as high as two pages per > second during brief periods. What kind of memory and paging metrics should > I use on FreeBSD systems? I'm not convinced that such a simple algorithm makes sense these days. If the system is normally pretty quiet, then it is unlikely you'll see any difference from optimizing memory behaviour further. I believe that when top(1) gives memory sizes, they are in bytes rather than pages as the manual indicates. -- Lowell Gilbert, embedded/networking software engineer, Boston area http://be-well.ilk.org/~lowell/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
