2015-07-10 14:53 GMT+09:00 Rob Landley <[email protected]>: > On 07/09/2015 05:41 AM, Yeongdeok Suh wrote: > > I discovered slow decompression while testing gunzip. > > I want to discuss about this improvement. > > > > I gunzipped an 15MB *.tar.gz file on the ARM board, and it takes around > > 17 sec. > > It's too slow, so I want to improve this for ARM based environment. > > (x86 was okay) > > So I looked at it some more and the deflate performance is kinda > pathetic, I did "time zcat linux-4.0.tar.gz > /dev/null" and toybox's > zcat is about half the speed of the ubuntu zcat. (I was going for simple > code and didn't particularly optimize it at all.) > > So I agree it could be faster and I'm all for speeding it up, but I need > to figure out where the slowness _is_ first. >
Actually, I'm analyzing the gzip inflate mechanism yet. As you said, the code is simple but I think it can be improved. If I have any idea about this, I'll share via mailing list. > > > As I debugged the src, > > below while loop takes too much time when decoded huffman symbol is over > > 256. > > Could you tell me how you "debugged the src"? (What profiling tool did > you use?) > I didn't use anything special tools. I'm using gdb, and I just checked speed of some code blocks via clock() function. > Rob >
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