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Mon, 25 Dec 2023 04:03:08 -0800 (PST) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20231208061407.2125867-1-yuzhao@google.com> In-Reply-To: From: Kairui Song Date: Mon, 25 Dec 2023 20:02:49 +0800 Message-ID: Subject: Re: [PATCH mm-unstable v1 1/4] mm/mglru: fix underprotected page cache To: Yu Zhao Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Charan Teja Kalla , Kalesh Singh , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Yu Zhao =E4=BA=8E2023=E5=B9=B412=E6=9C=8825=E6=97=A5=E5= =91=A8=E4=B8=80 14:30=E5=86=99=E9=81=93=EF=BC=9A > > On Wed, Dec 20, 2023 at 1:24=E2=80=AFAM Kairui Song wr= ote: > > > > Yu Zhao =E4=BA=8E2023=E5=B9=B412=E6=9C=8820=E6=97= =A5=E5=91=A8=E4=B8=89 16:17=E5=86=99=E9=81=93=EF=BC=9A > > > > > > On Tue, Dec 19, 2023 at 11:38=E2=80=AFPM Yu Zhao = wrote: > > > > > > > > On Tue, Dec 19, 2023 at 11:58=E2=80=AFAM Kairui Song wrote: > > > > > > > > > > Yu Zhao =E4=BA=8E2023=E5=B9=B412=E6=9C=8819= =E6=97=A5=E5=91=A8=E4=BA=8C 11:45=E5=86=99=E9=81=93=EF=BC=9A > > > > > > > > > > > > On Mon, Dec 18, 2023 at 8:21=E2=80=AFPM Yu Zhao wrote: > > > > > > > > > > > > > > On Mon, Dec 18, 2023 at 11:05=E2=80=AFAM Kairui Song wrote: > > > > > > > > > > > > > > > > Yu Zhao =E4=BA=8E2023=E5=B9=B412=E6=9C= =8815=E6=97=A5=E5=91=A8=E4=BA=94 12:56=E5=86=99=E9=81=93=EF=BC=9A > > > > > > > > > > > > > > > > > > On Thu, Dec 14, 2023 at 04:51:00PM -0700, Yu Zhao wrote: > > > > > > > > > > On Thu, Dec 14, 2023 at 11:38=E2=80=AFAM Kairui Song wrote: > > > > > > > > > > > > > > > > > > > > > > Yu Zhao =E4=BA=8E2023=E5=B9=B412= =E6=9C=8814=E6=97=A5=E5=91=A8=E5=9B=9B 11:09=E5=86=99=E9=81=93=EF=BC=9A > > > > > > > > > > > > On Wed, Dec 13, 2023 at 12:59:14AM -0700, Yu Zhao w= rote: > > > > > > > > > > > > > On Tue, Dec 12, 2023 at 8:03=E2=80=AFPM Kairui So= ng wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > Kairui Song =E4=BA=8E2023=E5= =B9=B412=E6=9C=8812=E6=97=A5=E5=91=A8=E4=BA=8C 14:52=E5=86=99=E9=81=93=EF= =BC=9A > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Yu Zhao =E4=BA=8E2023=E5= =B9=B412=E6=9C=8812=E6=97=A5=E5=91=A8=E4=BA=8C 06:07=E5=86=99=E9=81=93=EF= =BC=9A > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Fri, Dec 8, 2023 at 1:24=E2=80=AFAM Kair= ui Song wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Yu Zhao =E4=BA=8E2023= =E5=B9=B412=E6=9C=888=E6=97=A5=E5=91=A8=E4=BA=94 14:14=E5=86=99=E9=81=93=EF= =BC=9A > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Unmapped folios accessed through file d= escriptors can be > > > > > > > > > > > > > > > > > > underprotected. Those folios are added = to the oldest generation based > > > > > > > > > > > > > > > > > > on: > > > > > > > > > > > > > > > > > > 1. The fact that they are less costly t= o reclaim (no need to walk the > > > > > > > > > > > > > > > > > > rmap and flush the TLB) and have les= s impact on performance (don't > > > > > > > > > > > > > > > > > > cause major PFs and can be non-block= ing if needed again). > > > > > > > > > > > > > > > > > > 2. The observation that they are likely= to be single-use. E.g., for > > > > > > > > > > > > > > > > > > client use cases like Android, its a= pps parse configuration files > > > > > > > > > > > > > > > > > > and store the data in heap (anon); f= or server use cases like MySQL, > > > > > > > > > > > > > > > > > > it reads from InnoDB files and holds= the cached data for tables in > > > > > > > > > > > > > > > > > > buffer pools (anon). > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > However, the oldest generation can be v= ery short lived, and if so, it > > > > > > > > > > > > > > > > > > doesn't provide the PID controller with= enough time to respond to a > > > > > > > > > > > > > > > > > > surge of refaults. (Note that the PID c= ontroller uses weighted > > > > > > > > > > > > > > > > > > refaults and those from evicted generat= ions only take a half of the > > > > > > > > > > > > > > > > > > whole weight.) In other words, for a sh= ort lived generation, the > > > > > > > > > > > > > > > > > > moving average smooths out the spike qu= ickly. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > To fix the problem: > > > > > > > > > > > > > > > > > > 1. For folios that are already on LRU, = if they can be beyond the > > > > > > > > > > > > > > > > > > tracking range of tiers, i.e., five = accesses through file > > > > > > > > > > > > > > > > > > descriptors, move them to the second= oldest generation to give them > > > > > > > > > > > > > > > > > > more time to age. (Note that tiers a= re used by the PID controller > > > > > > > > > > > > > > > > > > to statistically determine whether f= olios accessed multiple times > > > > > > > > > > > > > > > > > > through file descriptors are worth p= rotecting.) > > > > > > > > > > > > > > > > > > 2. When adding unmapped folios to LRU, = adjust the placement of them so > > > > > > > > > > > > > > > > > > that they are not too close to the t= ail. The effect of this is > > > > > > > > > > > > > > > > > > similar to the above. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Android, launching 55 apps sequentia= lly: > > > > > > > > > > > > > > > > > > Before A= fter Change > > > > > > > > > > > > > > > > > > workingset_refault_anon 25641024 2= 5598972 0% > > > > > > > > > > > > > > > > > > workingset_refault_file 115016834 1= 06178438 -8% > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Yu, > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks you for your amazing works on MGLR= U. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I believe this is the similar issue I was= trying to resolve previously: > > > > > > > > > > > > > > > > > https://lwn.net/Articles/945266/ > > > > > > > > > > > > > > > > > The idea is to use refault distance to de= cide if the page should be > > > > > > > > > > > > > > > > > place in oldest generation or some other = gen, which per my test, > > > > > > > > > > > > > > > > > worked very well, and we have been using = refault distance for MGLRU in > > > > > > > > > > > > > > > > > multiple workloads. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > There are a few issues left in my previou= s RFC series, like anon pages > > > > > > > > > > > > > > > > > in MGLRU shouldn't be considered, I wante= d to collect feedback or test > > > > > > > > > > > > > > > > > cases, but unfortunately it seems didn't = get too much attention > > > > > > > > > > > > > > > > > upstream. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I think both this patch and my previous s= eries are for solving the > > > > > > > > > > > > > > > > > file pages underpertected issue, and I di= d a quick test using this > > > > > > > > > > > > > > > > > series, for mongodb test, refault distanc= e seems still a better > > > > > > > > > > > > > > > > > solution (I'm not saying these two optimi= zation are mutually exclusive > > > > > > > > > > > > > > > > > though, just they do have some conflicts = in implementation and solving > > > > > > > > > > > > > > > > > similar problem): > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Previous result: > > > > > > > > > > > > > > > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D > > > > > > > > > > > > > > > > > Execution Results after 905 seconds > > > > > > > > > > > > > > > > > -----------------------------------------= ------------------------- > > > > > > > > > > > > > > > > > Executed Time (= =C2=B5s) Rate > > > > > > > > > > > > > > > > > STOCK_LEVEL 2542 2712157= 1486.2 0.09 txn/s > > > > > > > > > > > > > > > > > -----------------------------------------= ------------------------- > > > > > > > > > > > > > > > > > TOTAL 2542 2712157= 1486.2 0.09 txn/s > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > This patch: > > > > > > > > > > > > > > > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D > > > > > > > > > > > > > > > > > Execution Results after 900 seconds > > > > > > > > > > > > > > > > > -----------------------------------------= ------------------------- > > > > > > > > > > > > > > > > > Executed Time (= =C2=B5s) Rate > > > > > > > > > > > > > > > > > STOCK_LEVEL 1594 2706152= 2574.4 0.06 txn/s > > > > > > > > > > > > > > > > > -----------------------------------------= ------------------------- > > > > > > > > > > > > > > > > > TOTAL 1594 2706152= 2574.4 0.06 txn/s > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Unpatched version is always around ~500. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks for the test results! > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I think there are a few points here: > > > > > > > > > > > > > > > > > - Refault distance make use of page shado= w so it can better > > > > > > > > > > > > > > > > > distinguish evicted pages of different ac= cess pattern (re-access > > > > > > > > > > > > > > > > > distance). > > > > > > > > > > > > > > > > > - Throttled refault distance can help hol= d part of workingset when > > > > > > > > > > > > > > > > > memory is too small to hold the whole wor= kingset. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > So maybe part of this patch and the bits = of previous series can be > > > > > > > > > > > > > > > > > combined to work better on this issue, ho= w do you think? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > I'll try to find some time this week to loo= k at your RFC. It'd be a > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Yu, > > > > > > > > > > > > > > > > > > > > > > > > > > > > I'm working on V4 of the RFC now, which just up= date some comments, and > > > > > > > > > > > > > > skip anon page re-activation in refault path fo= r mglru which was not > > > > > > > > > > > > > > very helpful, only some tiny adjustment. > > > > > > > > > > > > > > And I found it easier to test with fio, using f= ollowing test script: > > > > > > > > > > > > > > > > > > > > > > > > > > > > #!/bin/bash > > > > > > > > > > > > > > swapoff -a > > > > > > > > > > > > > > > > > > > > > > > > > > > > modprobe brd rd_nr=3D1 rd_size=3D16777216 > > > > > > > > > > > > > > mkfs.ext4 /dev/ram0 > > > > > > > > > > > > > > mount /dev/ram0 /mnt > > > > > > > > > > > > > > > > > > > > > > > > > > > > mkdir -p /sys/fs/cgroup/benchmark > > > > > > > > > > > > > > cd /sys/fs/cgroup/benchmark > > > > > > > > > > > > > > > > > > > > > > > > > > > > echo 4G > memory.max > > > > > > > > > > > > > > echo $$ > cgroup.procs > > > > > > > > > > > > > > echo 3 > /proc/sys/vm/drop_caches > > > > > > > > > > > > > > > > > > > > > > > > > > > > fio -name=3Dmglru --numjobs=3D12 --directory=3D= /mnt --size=3D1024m \ > > > > > > > > > > > > > > --buffered=3D1 --ioengine=3Dio_uring = --iodepth=3D128 \ > > > > > > > > > > > > > > --iodepth_batch_submit=3D32 --iodepth= _batch_complete=3D32 \ > > > > > > > > > > > > > > --rw=3Drandread --random_distribution= =3Dzipf:0.5 --norandommap \ > > > > > > > > > > > > > > --time_based --ramp_time=3D5m --runti= me=3D5m --group_reporting > > > > > > > > > > > > > > > > > > > > > > > > > > > > zipf:0.5 is used here to simulate a cached read= with slight bias > > > > > > > > > > > > > > towards certain pages. > > > > > > > > > > > > > > Unpatched 6.7-rc4: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D6548MiB/s (6866MB/s), 6548MiB/s-6= 548MiB/s > > > > > > > > > > > > > > (6866MB/s-6866MB/s), io=3D1918GiB (2060GB), run= =3D300001-300001msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > Patched with RFC v4: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D7270MiB/s (7623MB/s), 7270MiB/s-7= 270MiB/s > > > > > > > > > > > > > > (7623MB/s-7623MB/s), io=3D2130GiB (2287GB), run= =3D300001-300001msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > Patched with this series: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D7098MiB/s (7442MB/s), 7098MiB/s-7= 098MiB/s > > > > > > > > > > > > > > (7442MB/s-7442MB/s), io=3D2079GiB (2233GB), run= =3D300002-300002msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > MGLRU off: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D6525MiB/s (6842MB/s), 6525MiB/s-6= 525MiB/s > > > > > > > > > > > > > > (6842MB/s-6842MB/s), io=3D1912GiB (2052GB), run= =3D300002-300002msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > - If I change zipf:0.5 to random: > > > > > > > > > > > > > > Unpatched 6.7-rc4: > > > > > > > > > > > > > > Patched with this series: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D5975MiB/s (6265MB/s), 5975MiB/s-5= 975MiB/s > > > > > > > > > > > > > > (6265MB/s-6265MB/s), io=3D1750GiB (1879GB), run= =3D300002-300002msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > Patched with RFC v4: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D5987MiB/s (6278MB/s), 5987MiB/s-5= 987MiB/s > > > > > > > > > > > > > > (6278MB/s-6278MB/s), io=3D1754GiB (1883GB), run= =3D300001-300001msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > Patched with this series: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D5839MiB/s (6123MB/s), 5839MiB/s-5= 839MiB/s > > > > > > > > > > > > > > (6123MB/s-6123MB/s), io=3D1711GiB (1837GB), run= =3D300001-300001msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > MGLRU off: > > > > > > > > > > > > > > Run status group 0 (all jobs): > > > > > > > > > > > > > > READ: bw=3D5689MiB/s (5965MB/s), 5689MiB/s-5= 689MiB/s > > > > > > > > > > > > > > (5965MB/s-5965MB/s), io=3D1667GiB (1790GB), run= =3D300003-300003msec > > > > > > > > > > > > > > > > > > > > > > > > > > > > fio uses ramdisk so LRU accuracy will have smal= ler impact. The Mongodb > > > > > > > > > > > > > > test I provided before uses a SATA SSD so it wi= ll have a much higher > > > > > > > > > > > > > > impact. I'll provides a script to setup the tes= t case and run it, it's > > > > > > > > > > > > > > more complex to setup than fio since involving = setting up multiple > > > > > > > > > > > > > > replicas and auth and hundreds of GB of test fi= xtures, I'm currently > > > > > > > > > > > > > > occupied by some other tasks but will try best = to send them out as > > > > > > > > > > > > > > soon as possible. > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks! Apparently your RFC did show better IOPS = with both access > > > > > > > > > > > > > patterns, which was a surprise to me because it h= ad higher refaults > > > > > > > > > > > > > and usually higher refautls result in worse perfo= rmance. > > > > > > > > > > > > > > > > > > And thanks for providing the refaults I requested for -- = your data > > > > > > > > > below confirms what I mentioned above: > > > > > > > > > > > > > > > > > > For fio: > > > > > > > > > Your RFC This series Chang= e > > > > > > > > > workingset_refault_file 628192729 596790506 -5% > > > > > > > > > IOPS 1862k 1830k -2% > > > > > > > > > > > > > > > > > > For MongoDB: > > > > > > > > > Your RFC This series Chang= e > > > > > > > > > workingset_refault_anon 10512 35277 +30% > > > > > > > > > workingset_refault_file 22751782 20335355 -11% > > > > > > > > > total 22762294 20370632 -11% > > > > > > > > > TPS 0.09 0.06 -33% > > > > > > > > > > > > > > > > > > For MongoDB, this series should be a big win (but apparen= tly it's not), > > > > > > > > > especially when using zram, since an anon refault should = be a lot > > > > > > > > > cheaper than a file refault. > > > > > > > > > > > > > > > > > > So, I'm baffled... > > > > > > > > > > > > > > > > > > One important detail I forgot to mention: based on your d= ata from > > > > > > > > > lru_gen_full, I think there is another difference between= our Kconfigs: > > > > > > > > > > > > > > > > > > Your Kconfig My Kconfig Max possible > > > > > > > > > LRU_REFS_WIDTH 1 2 2 > > > > > > > > > > > > > > > > Hi Yu, > > > > > > > > > > > > > > > > Thanks for the info, my fault, I forgot to update my config= as I was > > > > > > > > testing some other features. > > > > > > > > Buf after I changed LRU_REFS_WIDTH to 2 by disabling IDLE_P= AGE, thing > > > > > > > > got much worse for MongoDB test: > > > > > > > > > > > > > > > > With LRU_REFS_WIDTH =3D=3D 2: > > > > > > > > > > > > > > > > This patch: > > > > > > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > > > Execution Results after 919 seconds > > > > > > > > -----------------------------------------------------------= ------- > > > > > > > > Executed Time (=C2=B5s) Rate > > > > > > > > STOCK_LEVEL 488 27598136201.9 0.02 txn/= s > > > > > > > > -----------------------------------------------------------= ------- > > > > > > > > TOTAL 488 27598136201.9 0.02 txn/= s > > > > > > > > > > > > > > > > memcg 86 /system.slice/docker-1c3a90be9f0a072f5719332419= 550cd0e1455f2cd5863bc2780ca4d3f913ece5.scope > > > > > > > > node 0 > > > > > > > > 1 948187 0x 0x > > > > > > > > 0 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 1 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 2 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 3 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 2 948187 0 6051788=C2=B7 > > > > > > > > 0 0r 0e 0p = 11916r > > > > > > > > 66442e 0p > > > > > > > > 1 0r 0e 0p = 903r > > > > > > > > 16888e 0p > > > > > > > > 2 0r 0e 0p = 459r > > > > > > > > 9764e 0p > > > > > > > > 3 0r 0e 0p = 0r > > > > > > > > 0e 2874p > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 3 948187 1353160 6351=C2=B7 > > > > > > > > 0 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 1 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 2 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 3 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 4 73045 23573 12=C2=B7 > > > > > > > > 0 0R 0T 0 = 3498607R > > > > > > > > 4868605T 0=C2=B7 > > > > > > > > 1 0R 0T 0 = 3012246R > > > > > > > > 3270261T 0=C2=B7 > > > > > > > > 2 0R 0T 0 = 2498608R > > > > > > > > 2839104T 0=C2=B7 > > > > > > > > 3 0R 0T 0 = 0R > > > > > > > > 1983947T 0=C2=B7 > > > > > > > > 1486579L 0O 1380614Y = 2945N > > > > > > > > 2945F 2734A > > > > > > > > > > > > > > > > workingset_refault_anon 0 > > > > > > > > workingset_refault_file 18130598 > > > > > > > > > > > > > > > > total used free shared bu= ff/cache available > > > > > > > > Mem: 31978 6705 312 20 = 24960 24786 > > > > > > > > Swap: 31977 4 31973 > > > > > > > > > > > > > > > > RFC: > > > > > > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > > > Execution Results after 908 seconds > > > > > > > > -----------------------------------------------------------= ------- > > > > > > > > Executed Time (=C2=B5s) Rate > > > > > > > > STOCK_LEVEL 2252 27159962888.2 0.08 txn/= s > > > > > > > > -----------------------------------------------------------= ------- > > > > > > > > TOTAL 2252 27159962888.2 0.08 txn/= s > > > > > > > > > > > > > > > > workingset_refault_anon 22585 > > > > > > > > workingset_refault_file 22715256 > > > > > > > > > > > > > > > > memcg 66 /system.slice/docker-0989446ff78106e32d3f400a0c= f371c9a703281bded86d6d6bb1af706ebb25da.scope > > > > > > > > node 0 > > > > > > > > 22 563007 2274 1198225=C2=B7 > > > > > > > > 0 0r 1e 0p = 0r > > > > > > > > 697076e 0p > > > > > > > > 1 0r 0e 0p = 0r > > > > > > > > 0e 325661p > > > > > > > > 2 0r 0e 0p = 0r > > > > > > > > 0e 888728p > > > > > > > > 3 0r 0e 0p = 0r > > > > > > > > 0e 3602238p > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 23 532222 7525 4948747=C2=B7 > > > > > > > > 0 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 1 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 2 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 3 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 24 500367 1214667 3292=C2=B7 > > > > > > > > 0 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 1 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 2 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 3 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 0 0 0 = 0 > > > > > > > > 0 0=C2=B7 > > > > > > > > 25 469692 40797 466=C2=B7 > > > > > > > > 0 0R 271T 0 = 0R > > > > > > > > 1162165T 0=C2=B7 > > > > > > > > 1 0R 0T 0 = 774028R > > > > > > > > 1205332T 0=C2=B7 > > > > > > > > 2 0R 0T 0 = 0R > > > > > > > > 932484T 0=C2=B7 > > > > > > > > 3 0R 1T 0 = 0R > > > > > > > > 4252158T 0=C2=B7 > > > > > > > > 25178380L 156515O 23953602Y = 59234N > > > > > > > > 49391F 48664A > > > > > > > > > > > > > > > > total used free shared bu= ff/cache available > > > > > > > > Mem: 31978 6968 338 5 = 24671 24555 > > > > > > > > Swap: 31977 1533 30444 > > > > > > > > > > > > > > > > Using same mongodb config (a 3 replica cluster using the sa= me config): > > > > > > > > { > > > > > > > > "net": { > > > > > > > > "bindIpAll": true, > > > > > > > > "ipv6": false, > > > > > > > > "maxIncomingConnections": 10000, > > > > > > > > }, > > > > > > > > "setParameter": { > > > > > > > > "disabledSecureAllocatorDomains": "*" > > > > > > > > }, > > > > > > > > "replication": { > > > > > > > > "oplogSizeMB": 10480, > > > > > > > > "replSetName": "issa-tpcc_0" > > > > > > > > }, > > > > > > > > "security": { > > > > > > > > "keyFile": "/data/db/keyfile" > > > > > > > > }, > > > > > > > > "storage": { > > > > > > > > "dbPath": "/data/db/", > > > > > > > > "syncPeriodSecs": 60, > > > > > > > > "directoryPerDB": true, > > > > > > > > "wiredTiger": { > > > > > > > > "engineConfig": { > > > > > > > > "cacheSizeGB": 5 > > > > > > > > } > > > > > > > > } > > > > > > > > }, > > > > > > > > "systemLog": { > > > > > > > > "destination": "file", > > > > > > > > "logAppend": true, > > > > > > > > "logRotate": "rename", > > > > > > > > "path": "/data/db/mongod.log", > > > > > > > > "verbosity": 0 > > > > > > > > } > > > > > > > > } > > > > > > > > > > > > > > > > The test environment have 32g memory and 16 core. > > > > > > > > > > > > > > > > Per my analyze, the access pattern for the mongodb test is = that page > > > > > > > > will be re-access long after it's evicted so PID controller= won't > > > > > > > > protect higher tier. That RFC will make use of the long exi= sting > > > > > > > > shadow to do feedback to PID/Gen so the result will be much= better. > > > > > > > > Still need more adjusting though, will try to do a rebase o= n top of > > > > > > > > mm-unstable which includes your patch. > > > > > > > > > > > > > > > > I've no idea why the workingset_refault_* is higher in the = better > > > > > > > > case, this a clearly an IO bound workload, Memory and IO is= busy while > > > > > > > > CPU is not full... > > > > > > > > > > > > > > > > I've uploaded my local reproducer here: > > > > > > > > https://github.com/ryncsn/emm-test-project/tree/master/mong= o-cluster > > > > > > > > https://github.com/ryncsn/py-tpcc > > > > > > > > > > > > > > Thanks for the repos -- I'm trying them right now. Which Mong= oDB > > > > > > > version did you use? setup.sh didn't seem to install it. > > > > > > > > > > > > > > Also do you have a QEMU image? It'd be a lot easier for me to > > > > > > > duplicate the exact environment by looking into it. > > > > > > > > > > > > I ended up using docker.io/mongodb/mongodb-community-server:lat= est, > > > > > > and it's not working: > > > > > > > > > > > > # docker exec -it mongo-r1 mongosh --eval \ > > > > > > '"rs.initiate({ > > > > > > _id: "issa-tpcc_0", > > > > > > members: [ > > > > > > {_id: 0, host: "mongo-r1"}, > > > > > > {_id: 1, host: "mongo-r2"}, > > > > > > {_id: 2, host: "mongo-r3"} > > > > > > ] > > > > > > })"' > > > > > > Emulate Docker CLI using podman. Create /etc/containers/nodocke= r to quiet msg. > > > > > > Error: can only create exec sessions on running containers: con= tainer > > > > > > state improper > > > > > > > > > > Hi Yu, > > > > > > > > > > I've updated the test repo: > > > > > https://github.com/ryncsn/emm-test-project/tree/master/mongo-clus= ter > > > > > > > > > > I've tested it on top of latest Fedora Cloud Image 39 and it work= ed > > > > > well for me, the README now contains detailed and not hard to fol= low > > > > > steps to reproduce this test. > > > > > > > > Thanks. I was following the instructions down to the letter and it > > > > fell apart again at line 46 (./tpcc.py). > > > > > > I think you just broke it by > > > https://github.com/ryncsn/py-tpcc/commit/7b9b380d636cb84faa5b11b5562e= 531f924eeb7e > > > > > > (But it's also possible you actually wanted me to use this latest > > > commit but forgot to account for it in your instructions.) > > > > > > > Were you able to successfully run the benchmark on a fresh VM by > > > > following the instructions? If not, I'd appreciate it if you could = do > > > > so and document all the missing steps. > > > > Ah, you are right, I attempted to convert it to Python3 but found it > > only brought more trouble, so I gave up and the instruction is still > > using Python2. However I accidentally pushed the WIP python3 convert > > commit... I've reset the repo to > > https://github.com/ryncsn/py-tpcc/commit/86e862c5cf3b2d1f51e0297742fa83= 7c7a99ebf8, > > this is working well. Sorry for the inconvenient. > > Thanks -- I was able to reproduce results similar to yours. > Hi Yu, Thanks for the testing, and merry xmas. > It turned out the mystery (fewer refaults but worse performance) was caus= ed by > 13.89% 13.89% kswapd0 [kernel.vmlinux] [k] > __list_del_entry_valid_or_report I'm not sure about this, if the task is CPU bounded, this could explain. But it's not, the performance gap is larger when tested on slow IO device. The iostat output during my test run: avg-cpu: %user %nice %system %iowait %steal %idle 7.40 0.00 2.42 83.37 0.00 6.80 Device r/s w/s rkB/s wkB/s rrqm/s wrqm/s %rrqm %wrqm r_await w_await aqu-sz rareq-sz wareq-sz svctm %util vda 35.00 0.80 167.60 17.20 6.90 3.50 16.47 81.40 0.47 1.62 0.02 4.79 21.50 0.63 2.27 vdb 5999.30 4.80 104433.60 84.00 0.00 8.30 0.00 63.36 6.54 1.31 39.25 17.41 17.50 0.17 100.00 zram0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 You can see CPU is waiting for IO, %user is always around 10%. The hotspot you posted only take up 13.89% of the runtime, which shouldn't cause so much performance drop. > > Apparently Fedora has CONFIG_DEBUG_LIST=3Dy by default, and after I > turned it off (the only change I made), this series showed better TPS > (I used"--duration=3D10800" for more reliable results): > v6.7-rc6 RFC [1] change > total txns 25024 24672 +1% > workingset_refault_anon 573668 680248 -16% > workingset_refault_file 260631976 265808452 -2% I have disabled CONFIG_DEBUG_LIST when doing performance comparison test. I believe you are using higher performance SSD, so the bottle neck is CPU, and the RFC involves more lru/memcg counter update/iteration, so it is slower by 1%. > I think this is easy to explain: this series is "lazy", i.e., > deferring the protection to eviction time, whereas your RFC tries to > do it upfront, i.e., at (re)fault time. The advantage of the former is > that it has more up-to-date information because a folio that is hot > when it's faulted in doesn't mean it's still hot later when memory > pressure kicks in. The disadvantage is that it needs to protect folios > that are still hot at eviction time, by moving them to a younger > generation, where the slow down happened with CONFIG_DEBUG_LIST=3Dy. > > (It's not really a priority for me to investigate why > __list_del_entry_valid_or_report() is so heavy. Hopefully someone else > can shed some light on it.) I've just setup another cluster with high performance SSD, where now CPU is the bottle neck to better understand this. Will try to do more test to see if I can find out something.