![]() | |||||||||||||
Messages in this thread |
david@lang.hm wrote: > On Sun, 5 Aug 2007, Diego Calleja wrote: > >> El Sun, 5 Aug 2007 09:13:20 +0200, Ingo Molnar <mingo@elte.hu> escribió: >> >>> Measurements show that noatime helps 20-30% on regular desktop >>> workloads, easily 50% for kernel builds and much more than that (in >>> excess of 100%) for file-read-intense workloads. We cannot just walk >> >> >> And as everybody knows in servers is a popular practice to disable it. >> According to an interview to the kernel.org admins.... >> >> "Beyond that, Peter noted, "very little fancy is going on, and that is >> good >> because fancy is hard to maintain." He explained that the only fancy >> thing >> being done is that all filesystems are mounted noatime meaning that the >> system doesn't have to make writes to the filesystem for files which are >> simply being read, "that cut the load average in half." >> >> I bet that some people would consider such performance hit a bug... >> > > actually, it's popular practice to disable it by people who know how big > a hit it is and know how few programs use it. > > i've been a linux sysadmin for 10 years, and have known about noatime > for at least 7 years, but I always thought of it in the catagory of 'use > it only on your performance critical machines where you are trying to > extract every ounce of performance, and keep an eye out for things > misbehaving' > > I never imagined that itwas the 20%+ hit that is being described, and > with so little impact, or I would have switched to it across the board > years ago. > To get that magnitude you need slow disk with very fast CPU. It helps most of systems where the disk hardware is marginal or worse for the i/o load. Don't take that as typical. > I'll bet there are a lot of admins out there in the same boat. > > adding an option in the kernel to change the default sounds like a very > good first step, even if the default isn't changed today. > -- Bill Davidsen <davidsen@tmr.com> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
| Last update: 2007-08-10 06:05 [from the cache] ©2003-2008 | |||||||||||||