Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-04 Thread Gao Xiang
On Fri, Dec 04, 2020 at 04:50:14PM +0800, Chao Yu wrote: ... > > > > > About the speed, I think which is also limited to storage device and other > > conditions (I mean the CPU loading during the writeback might be different > > between lz4 and lz4hc-9 due to many other bounds, e.g. UFS 3.0 seq

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-04 Thread Chao Yu
Hi Xiang, On 2020/12/4 15:43, Gao Xiang wrote: Hi Chao, On Fri, Dec 04, 2020 at 03:09:20PM +0800, Chao Yu wrote: On 2020/12/4 8:31, Gao Xiang wrote: could make more sense), could you leave some CR numbers about these algorithms on typical datasets (enwik9, silisia.tar or else.) with 16k clust

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Gao Xiang
Hi Chao, On Fri, Dec 04, 2020 at 03:09:20PM +0800, Chao Yu wrote: > On 2020/12/4 8:31, Gao Xiang wrote: > > could make more sense), could you leave some CR numbers about these > > algorithms on typical datasets (enwik9, silisia.tar or else.) with 16k > > cluster size? > > Just from a quick test w

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Chao Yu
On 2020/12/4 8:31, Gao Xiang wrote: could make more sense), could you leave some CR numbers about these algorithms on typical datasets (enwik9, silisia.tar or else.) with 16k cluster size? Just from a quick test with enwik9 on vm: Original blocks:244382 lz4

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Gao Xiang
On Fri, Dec 04, 2020 at 11:11:03AM +0800, Chao Yu wrote: > On 2020/12/4 10:47, Gao Xiang wrote: ... > > > future (and add more dependency to algorithms, you might see BWT-based bzip2 > > removal patch > > Oops, is that really allowed? I don't this is a good idea...and I don't see > there > are

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Chao Yu
On 2020/12/4 10:47, Gao Xiang wrote: On Fri, Dec 04, 2020 at 10:38:08AM +0800, Chao Yu wrote: On 2020/12/4 10:06, Gao Xiang wrote: On Fri, Dec 04, 2020 at 09:56:27AM +0800, Chao Yu wrote: ... Keep lz4hc dirty data under writeback could block writeback, make kswapd busy, and direct memory

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Gao Xiang
On Fri, Dec 04, 2020 at 10:38:08AM +0800, Chao Yu wrote: > On 2020/12/4 10:06, Gao Xiang wrote: > > On Fri, Dec 04, 2020 at 09:56:27AM +0800, Chao Yu wrote: ... > > > > > Keep lz4hc dirty data under writeback could block writeback, make kswapd > > busy, and direct memory reclaim path, I guess t

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Chao Yu
On 2020/12/4 10:06, Gao Xiang wrote: On Fri, Dec 04, 2020 at 09:56:27AM +0800, Chao Yu wrote: Hi Xiang, On 2020/12/4 8:31, Gao Xiang wrote: Hi Chao, On Thu, Dec 03, 2020 at 11:32:34AM -0800, Eric Biggers wrote: ... What is the use case for storing the compression level on-disk? Keep in m

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Gao Xiang
On Fri, Dec 04, 2020 at 09:56:27AM +0800, Chao Yu wrote: > Hi Xiang, > > On 2020/12/4 8:31, Gao Xiang wrote: > > Hi Chao, > > > > On Thu, Dec 03, 2020 at 11:32:34AM -0800, Eric Biggers wrote: > > > > ... > > > > > > > > What is the use case for storing the compression level on-disk? > > > > >

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Chao Yu
Hi Xiang, On 2020/12/4 8:31, Gao Xiang wrote: Hi Chao, On Thu, Dec 03, 2020 at 11:32:34AM -0800, Eric Biggers wrote: ... What is the use case for storing the compression level on-disk? Keep in mind that compression levels are an implementation detail; the exact compressed data that is prod

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Chao Yu
On 2020/12/4 3:32, Eric Biggers wrote: On Thu, Dec 03, 2020 at 02:17:15PM +0800, Chao Yu wrote: +config F2FS_FS_LZ4HC + bool "LZ4HC compression support" + depends on F2FS_FS_COMPRESSION + depends on F2FS_FS_LZ4 + select LZ4HC_COMPRESS + default y + help +

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Gao Xiang
Hi Chao, On Thu, Dec 03, 2020 at 11:32:34AM -0800, Eric Biggers wrote: ... > > What is the use case for storing the compression level on-disk? > > Keep in mind that compression levels are an implementation detail; the exact > compressed data that is produced by a particular algorithm at a part

Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level

2020-12-03 Thread Eric Biggers
On Thu, Dec 03, 2020 at 02:17:15PM +0800, Chao Yu wrote: > +config F2FS_FS_LZ4HC > + bool "LZ4HC compression support" > + depends on F2FS_FS_COMPRESSION > + depends on F2FS_FS_LZ4 > + select LZ4HC_COMPRESS > + default y > + help > + Support LZ4HC compress algorithm, if