On Fri, 25 Oct 2013 07:25:13 +0000 (UTC) "Artem S. Tashkinov" <t.ar...@lycos.com> wrote:
> Hello! > > On my x86-64 PC (Intel Core i5 2500, 16GB RAM), I have the same 3.11 kernel > built for the i686 (with PAE) and x86-64 architectures. What's really > troubling me > is that the x86-64 kernel has the following problem: > > When I copy large files to any storage device, be it my HDD with ext4 > partitions > or flash drive with FAT32 partitions, the kernel first caches them in memory > entirely > then flushes them some time later (quite unpredictably though) or immediately > upon > invoking "sync". > > How can I disable this memory cache altogether (or at least minimize > caching)? When > running the i686 kernel with the same configuration I don't observe this > effect - files get > written out almost immediately (for instance "sync" takes less than a second, > whereas > on x86-64 it can take a dozen of _minutes_ depending on a file size and > storage > performance). What exactly is bothering you about this? The amount of memory used or the time until data is flushed? If the later, then /proc/sys/vm/dirty_expire_centisecs is where you want to look. This defaults to 30 seconds (3000 centisecs). You could make it smaller (providing you also shrink dirty_writeback_centisecs in a similar ratio) and the VM will flush out data more quickly. NeilBrown > > I'm _not_ talking about disabling write cache on my storage itself (hdparm -W > 0 /dev/XXX) > - firstly this command is detrimental to the performance of my PC, secondly, > it won't help > in this instance. > > Swap is totally disabled, usually my memory is entirely free. > > My kernel configuration can be fetched here: > https://bugzilla.kernel.org/show_bug.cgi?id=63531 > > Please, advise. > > Best regards, > > Artem > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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