On Thu, 25 Jan 2007 00:40:54 -0500 Rik van Riel <[EMAIL PROTECTED]> wrote:
> KAMEZAWA Hiroyuki wrote: > > On Wed, 24 Jan 2007 23:28:15 -0500 > > Rik van Riel <[EMAIL PROTECTED]> wrote: > > > >> KAMEZAWA Hiroyuki wrote: > > I always says Linux is different from mainframes. > > It's not just about Linux. > > Applications behave differently too from the way they were 15 > years ago. > > Some databases, eg. sleepycat's db, map the whole database in > memory. Other databases, like MySQL and postgresql, rely on > the kernel's page cache to cache the most frequently accessed > data. > > To make matters more interesting, memory sizes have increased > by a factor 1000, but disk seek times have only gotten 10 times > faster. This means that simplistic memory management algorithms > can hurt performance a lot more than they could back then. > > In short, I am not convinced that any of the simple tunable knobs > from the "good old days" will do much to actually help people > with modern workloads on modern computers. > I agree. My current concerns is not adding knobs but how to show/explain what the users does. In most case, users don't know what they does and believes system-information can tell that. for example) A user sometimes asks "why amount of system-A's pagecache and system-B's are different from each other ?. I definitly does the same jobs on the both system." ...just because he used different deta-set ;) Thanks, -Kame - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/