Messages in this thread | | | Date | Tue, 30 Aug 2022 22:31:19 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH v2] riscv: enable THP_SWAP for RV64 |
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On Tue, Aug 30, 2022 at 02:26:38PM +0000, Conor.Dooley@microchip.com wrote: > On 30/08/2022 15:15, Conor Dooley - M52691 wrote: > > On 30/08/2022 14:59, Jisheng Zhang wrote: > >> On Mon, Aug 29, 2022 at 05:27:48PM +0000, Conor.Dooley@microchip.com wrote: > >>> On 29/08/2022 15:10, Jisheng Zhang wrote: > >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > >>>> > >>>> On Sat, Aug 27, 2022 at 09:13:03PM +0000, Conor.Dooley@microchip.com wrote: > >>>>> Hey Jisheng, > >>>> > >>>> Hi Conor, > >>>> > >>>>> On 27/08/2022 10:58, Jisheng Zhang wrote: > >>>>>> I have a Sipeed Lichee RV dock board which only has 512MB DDR, so > >>>>>> memory optimizations such as swap on zram are helpful. As is seen > >>>>>> in commit d0637c505f8a ("arm64: enable THP_SWAP for arm64") and > >>>>>> commit bd4c82c22c367e ("mm, THP, swap: delay splitting THP after > >>>>>> swapped out"), THP_SWAP can improve the swap throughput significantly. > >>>>>> > >>>>>> Enable THP_SWAP for RV64, testing the micro-benchmark which is > >>>>>> introduced by commit d0637c505f8a ("arm64: enable THP_SWAP for arm64") > >>>>>> shows below numbers on the Lichee RV dock board: > >>>>>> > >>>>>> thp swp throughput w/o patch: 66908 bytes/ms (mean of 10 tests) > >>>>>> thp swp throughput w/ patch: 322638 bytes/ms (mean of 10 tests) > >>>>> > >>>>> I know the original commit message contains this, but it's a little > >>>>> odd. If the patch /enables/ THP then how would there be THP swap > >>>>> prior to the patch? > >>>> > >>>> hmm, it's swap I'll send a v3 to correct the description. > >>>> > >>>>> > >>>>>> > >>>>>> Improved by 382%! > >>>>> > >>>>> I could not replicate the after numbers on my nezha, so I suspect > >>>>> I am missing something in my config/setup. zswap is enabled and is > >>>> > >>>> swap on zram rather than zswap ;) > >>> > >>> I think I tried about 30 different config variations, initially not > >>> using zswap and later using it. > >>> My zramctl looks like so (although I did try zstd too) after running > >>> the demo application from that commit: > >>> > >>> NAME ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS MOUNTPOINT > >>> /dev/zram0 lzo-rle 241M 22M 8.4M 9.1M 1 [SWAP] > >>> > >>> I am using the default riscv defconfig + the following: > >>> CONFIG_ZRAM=y > >>> CONFIG_CRYPTO_DEFLATE=y > >>> CONFIG_CRYPTO_LZO=y > >>> CONFIG_CRYPTO_ZSTD=y > >>> CONFIG_ZRAM_MEMORY_TRACKING=y > >>> CONFIG_TRANSPARENT_HUGEPAGE=y > >>> CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y > >>> CONFIG_THP_SWAP=y > >>> > >>> Am I just missing something obvious here? > >> > >> similar config options here. what's your rootfs? Is your board busy > >> with something? I used a minimal rootfs built from buildroot. > >> can you plz show your numbers w/ and w/o the patch? > > > > I was using fedora for the testing, downloaded directly from > > koji. My before/after numbers varied, but were around 80,000 > > bytes/ms most of the time. > > > > If I increased the size to 500 * 1024 * 1024 I got around 130k. > > 130k before & after.** > > > > > Before/after the patch, the numbers did not really change, but > > things did fluctuate quite wildly - from about 50k to 90k using > > the 400 size. > > What I mean is: before/after the patch had visible performance > difference because it was always flucuating in the same range.
I see the difference -- w/ minial buildroot rootfs, the numbers isn't kept the same but the difference is trivial, I even got two or three the same numbers during 10 times of testing. But your numbers were always flucuating, so I guess your system maybe busy with with something in a shore period, I.E the os env is full of noise.
I guess you may get similar improvement percentage when trying buildroot > > > > >> > >> I also tried the simple benchmark on qemu(just for reference, since > >> I have no other riscv boards except the lichee RV dock board): > >> swp out w/o patch: 30066 bytes/ms (mean of 10 tests) > >> swp out w/ patch: 130055 bytes/ms (mean of 10 tests) > >> so improved by 332.7% > > > > I'll give QEMU a go so :) >
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