Messages in this thread | | | Date | Fri, 01 Feb 2013 17:15:00 +0900 | From | "kyungsik.lee" <> | Subject | Re: [RFC PATCH 0/4] Add support for LZ4-compressed kernels |
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On 2013-01-29 오후 8:43, Egon Alter wrote: > Am Dienstag, 29. Januar 2013, 10:15:49 schrieb Russell King - ARM Linux: >> On Mon, Jan 28, 2013 at 02:25:10PM -0800, Andrew Morton wrote: >>> What's this "with enabled unaligned memory access" thing? You mean "if >>> the arch supports CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS"? If so, >>> that's only x86, which isn't really in the target market for this >>> patch, yes? >>> >>> It's a lot of code for a 50ms boot-time improvement. Does anyone have >>> any opinions on whether or not the benefits are worth the cost? >> Well... when I saw this my immediate reaction was "oh no, yet another >> decompressor for the kernel". We have five of these things already. >> Do we really need a sixth? >> >> My feeling is that we should have: >> - one decompressor which is the fastest >> - one decompressor for the highest compression ratio >> - one popular decompressor (eg conventional gzip) > the problem gets more complicated as the "fastest" decompressor usually > creates larger images which need more time to load from the storage, e.g. a > one MB larger image on a 10 MB/s storage (note: bootloaders often configure > the storage controllers in slow modes) gives 100 ms more boot time, thus > eating the gain of a "fast decompressor". Yes, the larger image could matter. Definitely it takes longer.
Here are some updated test cases: Including "loading time"
lzo lz4 loading time: 480ms 510ms decompression time: 336ms 180ms(with efficient unaligned memory access enabled and ARM optimization) total time: 816ms 690ms
lz4 is still 15% faster in total time. This one is similar to the simulated result by Russell King.
Thanks, Kyungsik -- 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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