Messages in this thread | | | Date | Thu, 10 Oct 2002 16:39:27 +0200 | From | "J.A. Magallon" <> | Subject | Re: More on O_STREAMING (goodby read pauses) |
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On 2002.10.10 Mark Mielke wrote: >On Wed, Oct 09, 2002 at 06:43:52PM -0400, Robert Love wrote: >> On Wed, 2002-10-09 at 18:23, J.A. Magallon wrote: >> > But I did the test with an addition: read a 1Gb file and print an '*' >> > after every 10M. Without O_STREAMING, when memory fills, the 'progress >> > bar' stalls for a few seconds while pages are sent to disk. >> > So the patch also favours a constant sustained rate of read from the >> > disk. Very interesting for things like video edition and so on. >> > I like it ;). >> This is 100% the point of the patch and hopefully the point I proved >> when I first posted it. > >I assume the stall is not 'while pages are sent to disk', but rather >until kswapd gets around to freeing enough pages to allow memory to >fill again. The stall is due to the pages being fully analyzed to >determine which ones should go, and which ones shouldn't. O_STREAMING >removes the pages ahead of time, so no analysis is ever required. >
I can _hear_ the disk activity when the stall happens, so selecting what to drop is fast, but then you have to write it...
-- J.A. Magallon <jamagallon@able.es> \ Software is like sex: werewolf.able.es \ It's better when it's free Mandrake Linux release 9.1 (Cooker) for i586 Linux 2.4.20-pre10-jam1 (gcc 3.2 (Mandrake Linux 9.0 3.2-2mdk)) - 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/
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