Hi Haiyan, Do you get a chance to capture some performance cycles on your system ? I still can't get these numbers on my hardware. Thanks, Laurent. On 04/07/2018 09:51, Laurent Dufour wrote: > On 04/07/2018 05:23, Song, HaiyanX wrote: >> Hi Laurent, >> >> >> For the test result on Intel 4s skylake platform (192 CPUs, 768G Memory), the below test cases all were run 3 times. >> I check the test results, only page_fault3_thread/enable THP have 6% stddev for head commit, other tests have lower stddev. > > Repeating the test only 3 times seems a bit too low to me. > > I'll focus on the higher change for the moment, but I don't have access to such > a hardware. > > Is possible to provide a diff between base and SPF of the performance cycles > measured when running page_fault3 and page_fault2 when the 20% change is detected. > > Please stay focus on the test case process to see exactly where the series is > impacting. > > Thanks, > Laurent. > >> >> And I did not find other high variation on test case result. >> >> a). Enable THP >> testcase base stddev change head stddev metric >> page_fault3/enable THP 10519 ± 3% -20.5% 8368 ±6% will-it-scale.per_thread_ops >> page_fault2/enalbe THP 8281 ± 2% -18.8% 6728 will-it-scale.per_thread_ops >> brk1/eanble THP 998475 -2.2% 976893 will-it-scale.per_process_ops >> context_switch1/enable THP 223910 -1.3% 220930 will-it-scale.per_process_ops >> context_switch1/enable THP 233722 -1.0% 231288 will-it-scale.per_thread_ops >> >> b). Disable THP >> page_fault3/disable THP 10856 -23.1% 8344 will-it-scale.per_thread_ops >> page_fault2/disable THP 8147 -18.8% 6613 will-it-scale.per_thread_ops >> brk1/disable THP 957 -7.9% 881 will-it-scale.per_thread_ops >> context_switch1/disable THP 237006 -2.2% 231907 will-it-scale.per_thread_ops >> brk1/disable THP 997317 -2.0% 977778 will-it-scale.per_process_ops >> page_fault3/disable THP 467454 -1.8% 459251 will-it-scale.per_process_ops >> context_switch1/disable THP 224431 -1.3% 221567 will-it-scale.per_process_ops >> >> >> Best regards, >> Haiyan Song >> ________________________________________ >> From: Laurent Dufour [ldufour@xxxxxxxxxxxxxxxxxx] >> Sent: Monday, July 02, 2018 4:59 PM >> To: Song, HaiyanX >> Cc: akpm@xxxxxxxxxxxxxxxxxxxx; mhocko@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; kirill@xxxxxxxxxxxxx; ak@xxxxxxxxxxxxxxx; dave@xxxxxxxxxxxx; jack@xxxxxxx; Matthew Wilcox; khandual@xxxxxxxxxxxxxxxxxx; aneesh.kumar@xxxxxxxxxxxxxxxxxx; benh@xxxxxxxxxxxxxxxxxxx; mpe@xxxxxxxxxxxxxx; paulus@xxxxxxxxx; Thomas Gleixner; Ingo Molnar; hpa@xxxxxxxxx; Will Deacon; Sergey Senozhatsky; sergey.senozhatsky.work@xxxxxxxxx; Andrea Arcangeli; Alexei Starovoitov; Wang, Kemi; Daniel Jordan; David Rientjes; Jerome Glisse; Ganesh Mahendran; Minchan Kim; Punit Agrawal; vinayak menon; Yang Shi; linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; haren@xxxxxxxxxxxxxxxxxx; npiggin@xxxxxxxxx; bsingharora@xxxxxxxxx; paulmck@xxxxxxxxxxxxxxxxxx; Tim Chen; linuxppc-dev@xxxxxxxxxxxxxxxx; x86@xxxxxxxxxx >> Subject: Re: [PATCH v11 00/26] Speculative page faults >> >> On 11/06/2018 09:49, Song, HaiyanX wrote: >>> Hi Laurent, >>> >>> Regression test for v11 patch serials have been run, some regression is found by LKP-tools (linux kernel performance) >>> tested on Intel 4s skylake platform. This time only test the cases which have been run and found regressions on >>> V9 patch serials. >>> >>> The regression result is sorted by the metric will-it-scale.per_thread_ops. >>> branch: Laurent-Dufour/Speculative-page-faults/20180520-045126 >>> commit id: >>> head commit : a7a8993bfe3ccb54ad468b9f1799649e4ad1ff12 >>> base commit : ba98a1cdad71d259a194461b3a61471b49b14df1 >>> Benchmark: will-it-scale >>> Download link: https://github.com/antonblanchard/will-it-scale/tree/master >>> >>> Metrics: >>> will-it-scale.per_process_ops=processes/nr_cpu >>> will-it-scale.per_thread_ops=threads/nr_cpu >>> test box: lkp-skl-4sp1(nr_cpu=192,memory=768G) >>> THP: enable / disable >>> nr_task:100% >>> >>> 1. Regressions: >>> >>> a). Enable THP >>> testcase base change head metric >>> page_fault3/enable THP 10519 -20.5% 836 will-it-scale.per_thread_ops >>> page_fault2/enalbe THP 8281 -18.8% 6728 will-it-scale.per_thread_ops >>> brk1/eanble THP 998475 -2.2% 976893 will-it-scale.per_process_ops >>> context_switch1/enable THP 223910 -1.3% 220930 will-it-scale.per_process_ops >>> context_switch1/enable THP 233722 -1.0% 231288 will-it-scale.per_thread_ops >>> >>> b). Disable THP >>> page_fault3/disable THP 10856 -23.1% 8344 will-it-scale.per_thread_ops >>> page_fault2/disable THP 8147 -18.8% 6613 will-it-scale.per_thread_ops >>> brk1/disable THP 957 -7.9% 881 will-it-scale.per_thread_ops >>> context_switch1/disable THP 237006 -2.2% 231907 will-it-scale.per_thread_ops >>> brk1/disable THP 997317 -2.0% 977778 will-it-scale.per_process_ops >>> page_fault3/disable THP 467454 -1.8% 459251 will-it-scale.per_process_ops >>> context_switch1/disable THP 224431 -1.3% 221567 will-it-scale.per_process_ops >>> >>> Notes: for the above values of test result, the higher is better. >> >> I tried the same tests on my PowerPC victim VM (1024 CPUs, 11TB) and I can't >> get reproducible results. The results have huge variation, even on the vanilla >> kernel, and I can't state on any changes due to that. >> >> I tried on smaller node (80 CPUs, 32G), and the tests ran better, but I didn't >> measure any changes between the vanilla and the SPF patched ones: >> >> test THP enabled 4.17.0-rc4-mm1 spf delta >> page_fault3_threads 2697.7 2683.5 -0.53% >> page_fault2_threads 170660.6 169574.1 -0.64% >> context_switch1_threads 6915269.2 6877507.3 -0.55% >> context_switch1_processes 6478076.2 6529493.5 0.79% >> brk1 243391.2 238527.5 -2.00% >> >> Tests were run 10 times, no high variation detected. >> >> Did you see high variation on your side ? How many times the test were run to >> compute the average values ? >> >> Thanks, >> Laurent. >> >> >>> >>> 2. Improvement: not found improvement based on the selected test cases. >>> >>> >>> Best regards >>> Haiyan Song >>> ________________________________________ >>> From: owner-linux-mm@xxxxxxxxx [owner-linux-mm@xxxxxxxxx] on behalf of Laurent Dufour [ldufour@xxxxxxxxxxxxxxxxxx] >>> Sent: Monday, May 28, 2018 4:54 PM >>> To: Song, HaiyanX >>> Cc: akpm@xxxxxxxxxxxxxxxxxxxx; mhocko@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; kirill@xxxxxxxxxxxxx; ak@xxxxxxxxxxxxxxx; dave@xxxxxxxxxxxx; jack@xxxxxxx; Matthew Wilcox; khandual@xxxxxxxxxxxxxxxxxx; aneesh.kumar@xxxxxxxxxxxxxxxxxx; benh@xxxxxxxxxxxxxxxxxxx; mpe@xxxxxxxxxxxxxx; paulus@xxxxxxxxx; Thomas Gleixner; Ingo Molnar; hpa@xxxxxxxxx; Will Deacon; Sergey Senozhatsky; sergey.senozhatsky.work@xxxxxxxxx; Andrea Arcangeli; Alexei Starovoitov; Wang, Kemi; Daniel Jordan; David Rientjes; Jerome Glisse; Ganesh Mahendran; Minchan Kim; Punit Agrawal; vinayak menon; Yang Shi; linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; haren@xxxxxxxxxxxxxxxxxx; npiggin@xxxxxxxxx; bsingharora@xxxxxxxxx; paulmck@xxxxxxxxxxxxxxxxxx; Tim Chen; linuxppc-dev@xxxxxxxxxxxxxxxx; x86@xxxxxxxxxx >>> Subject: Re: [PATCH v11 00/26] Speculative page faults >>> >>> On 28/05/2018 10:22, Haiyan Song wrote: >>>> Hi Laurent, >>>> >>>> Yes, these tests are done on V9 patch. >>> >>> Do you plan to give this V11 a run ? >>> >>>> >>>> >>>> Best regards, >>>> Haiyan Song >>>> >>>> On Mon, May 28, 2018 at 09:51:34AM +0200, Laurent Dufour wrote: >>>>> On 28/05/2018 07:23, Song, HaiyanX wrote: >>>>>> >>>>>> Some regression and improvements is found by LKP-tools(linux kernel performance) on V9 patch series >>>>>> tested on Intel 4s Skylake platform. >>>>> >>>>> Hi, >>>>> >>>>> Thanks for reporting this benchmark results, but you mentioned the "V9 patch >>>>> series" while responding to the v11 header series... >>>>> Were these tests done on v9 or v11 ? >>>>> >>>>> Cheers, >>>>> Laurent. >>>>> >>>>>> >>>>>> The regression result is sorted by the metric will-it-scale.per_thread_ops. >>>>>> Branch: Laurent-Dufour/Speculative-page-faults/20180316-151833 (V9 patch series) >>>>>> Commit id: >>>>>> base commit: d55f34411b1b126429a823d06c3124c16283231f >>>>>> head commit: 0355322b3577eeab7669066df42c550a56801110 >>>>>> Benchmark suite: will-it-scale >>>>>> Download link: >>>>>> https://github.com/antonblanchard/will-it-scale/tree/master/tests >>>>>> Metrics: >>>>>> will-it-scale.per_process_ops=processes/nr_cpu >>>>>> will-it-scale.per_thread_ops=threads/nr_cpu >>>>>> test box: lkp-skl-4sp1(nr_cpu=192,memory=768G) >>>>>> THP: enable / disable >>>>>> nr_task: 100% >>>>>> >>>>>> 1. Regressions: >>>>>> a) THP enabled: >>>>>> testcase base change head metric >>>>>> page_fault3/ enable THP 10092 -17.5% 8323 will-it-scale.per_thread_ops >>>>>> page_fault2/ enable THP 8300 -17.2% 6869 will-it-scale.per_thread_ops >>>>>> brk1/ enable THP 957.67 -7.6% 885 will-it-scale.per_thread_ops >>>>>> page_fault3/ enable THP 172821 -5.3% 163692 will-it-scale.per_process_ops >>>>>> signal1/ enable THP 9125 -3.2% 8834 will-it-scale.per_process_ops >>>>>> >>>>>> b) THP disabled: >>>>>> testcase base change head metric >>>>>> page_fault3/ disable THP 10107 -19.1% 8180 will-it-scale.per_thread_ops >>>>>> page_fault2/ disable THP 8432 -17.8% 6931 will-it-scale.per_thread_ops >>>>>> context_switch1/ disable THP 215389 -6.8% 200776 will-it-scale.per_thread_ops >>>>>> brk1/ disable THP 939.67 -6.6% 877.33 will-it-scale.per_thread_ops >>>>>> page_fault3/ disable THP 173145 -4.7% 165064 will-it-scale.per_process_ops >>>>>> signal1/ disable THP 9162 -3.9% 8802 will-it-scale.per_process_ops >>>>>> >>>>>> 2. Improvements: >>>>>> a) THP enabled: >>>>>> testcase base change head metric >>>>>> malloc1/ enable THP 66.33 +469.8% 383.67 will-it-scale.per_thread_ops >>>>>> writeseek3/ enable THP 2531 +4.5% 2646 will-it-scale.per_thread_ops >>>>>> signal1/ enable THP 989.33 +2.8% 1016 will-it-scale.per_thread_ops >>>>>> >>>>>> b) THP disabled: >>>>>> testcase base change head metric >>>>>> malloc1/ disable THP 90.33 +417.3% 467.33 will-it-scale.per_thread_ops >>>>>> read2/ disable THP 58934 +39.2% 82060 will-it-scale.per_thread_ops >>>>>> page_fault1/ disable THP 8607 +36.4% 11736 will-it-scale.per_thread_ops >>>>>> read1/ disable THP 314063 +12.7% 353934 will-it-scale.per_thread_ops >>>>>> writeseek3/ disable THP 2452 +12.5% 2759 will-it-scale.per_thread_ops >>>>>> signal1/ disable THP 971.33 +5.5% 1024 will-it-scale.per_thread_ops >>>>>> >>>>>> Notes: for above values in column "change", the higher value means that the related testcase result >>>>>> on head commit is better than that on base commit for this benchmark. >>>>>> >>>>>> >>>>>> Best regards >>>>>> Haiyan Song >>>>>> >>>>>> ________________________________________ >>>>>> From: owner-linux-mm@xxxxxxxxx [owner-linux-mm@xxxxxxxxx] on behalf of Laurent Dufour [ldufour@xxxxxxxxxxxxxxxxxx] >>>>>> Sent: Thursday, May 17, 2018 7:06 PM >>>>>> To: akpm@xxxxxxxxxxxxxxxxxxxx; mhocko@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; kirill@xxxxxxxxxxxxx; ak@xxxxxxxxxxxxxxx; dave@xxxxxxxxxxxx; jack@xxxxxxx; Matthew Wilcox; khandual@xxxxxxxxxxxxxxxxxx; aneesh.kumar@xxxxxxxxxxxxxxxxxx; benh@xxxxxxxxxxxxxxxxxxx; mpe@xxxxxxxxxxxxxx; paulus@xxxxxxxxx; Thomas Gleixner; Ingo Molnar; hpa@xxxxxxxxx; Will Deacon; Sergey Senozhatsky; sergey.senozhatsky.work@xxxxxxxxx; Andrea Arcangeli; Alexei Starovoitov; Wang, Kemi; Daniel Jordan; David Rientjes; Jerome Glisse; Ganesh Mahendran; Minchan Kim; Punit Agrawal; vinayak menon; Yang Shi >>>>>> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; haren@xxxxxxxxxxxxxxxxxx; npiggin@xxxxxxxxx; bsingharora@xxxxxxxxx; paulmck@xxxxxxxxxxxxxxxxxx; Tim Chen; linuxppc-dev@xxxxxxxxxxxxxxxx; x86@xxxxxxxxxx >>>>>> Subject: [PATCH v11 00/26] Speculative page faults >>>>>> >>>>>> This is a port on kernel 4.17 of the work done by Peter Zijlstra to handle >>>>>> page fault without holding the mm semaphore [1]. >>>>>> >>>>>> The idea is to try to handle user space page faults without holding the >>>>>> mmap_sem. This should allow better concurrency for massively threaded >>>>>> process since the page fault handler will not wait for other threads memory >>>>>> layout change to be done, assuming that this change is done in another part >>>>>> of the process's memory space. This type page fault is named speculative >>>>>> page fault. If the speculative page fault fails because of a concurrency is >>>>>> detected or because underlying PMD or PTE tables are not yet allocating, it >>>>>> is failing its processing and a classic page fault is then tried. >>>>>> >>>>>> The speculative page fault (SPF) has to look for the VMA matching the fault >>>>>> address without holding the mmap_sem, this is done by introducing a rwlock >>>>>> which protects the access to the mm_rb tree. Previously this was done using >>>>>> SRCU but it was introducing a lot of scheduling to process the VMA's >>>>>> freeing operation which was hitting the performance by 20% as reported by >>>>>> Kemi Wang [2]. Using a rwlock to protect access to the mm_rb tree is >>>>>> limiting the locking contention to these operations which are expected to >>>>>> be in a O(log n) order. In addition to ensure that the VMA is not freed in >>>>>> our back a reference count is added and 2 services (get_vma() and >>>>>> put_vma()) are introduced to handle the reference count. Once a VMA is >>>>>> fetched from the RB tree using get_vma(), it must be later freed using >>>>>> put_vma(). I can't see anymore the overhead I got while will-it-scale >>>>>> benchmark anymore. >>>>>> >>>>>> The VMA's attributes checked during the speculative page fault processing >>>>>> have to be protected against parallel changes. This is done by using a per >>>>>> VMA sequence lock. This sequence lock allows the speculative page fault >>>>>> handler to fast check for parallel changes in progress and to abort the >>>>>> speculative page fault in that case. >>>>>> >>>>>> Once the VMA has been found, the speculative page fault handler would check >>>>>> for the VMA's attributes to verify that the page fault has to be handled >>>>>> correctly or not. Thus, the VMA is protected through a sequence lock which >>>>>> allows fast detection of concurrent VMA changes. If such a change is >>>>>> detected, the speculative page fault is aborted and a *classic* page fault >>>>>> is tried. VMA sequence lockings are added when VMA attributes which are >>>>>> checked during the page fault are modified. >>>>>> >>>>>> When the PTE is fetched, the VMA is checked to see if it has been changed, >>>>>> so once the page table is locked, the VMA is valid, so any other changes >>>>>> leading to touching this PTE will need to lock the page table, so no >>>>>> parallel change is possible at this time. >>>>>> >>>>>> The locking of the PTE is done with interrupts disabled, this allows >>>>>> checking for the PMD to ensure that there is not an ongoing collapsing >>>>>> operation. Since khugepaged is firstly set the PMD to pmd_none and then is >>>>>> waiting for the other CPU to have caught the IPI interrupt, if the pmd is >>>>>> valid at the time the PTE is locked, we have the guarantee that the >>>>>> collapsing operation will have to wait on the PTE lock to move forward. >>>>>> This allows the SPF handler to map the PTE safely. If the PMD value is >>>>>> different from the one recorded at the beginning of the SPF operation, the >>>>>> classic page fault handler will be called to handle the operation while >>>>>> holding the mmap_sem. As the PTE lock is done with the interrupts disabled, >>>>>> the lock is done using spin_trylock() to avoid dead lock when handling a >>>>>> page fault while a TLB invalidate is requested by another CPU holding the >>>>>> PTE. >>>>>> >>>>>> In pseudo code, this could be seen as: >>>>>> speculative_page_fault() >>>>>> { >>>>>> vma = get_vma() >>>>>> check vma sequence count >>>>>> check vma's support >>>>>> disable interrupt >>>>>> check pgd,p4d,...,pte >>>>>> save pmd and pte in vmf >>>>>> save vma sequence counter in vmf >>>>>> enable interrupt >>>>>> check vma sequence count >>>>>> handle_pte_fault(vma) >>>>>> .. >>>>>> page = alloc_page() >>>>>> pte_map_lock() >>>>>> disable interrupt >>>>>> abort if sequence counter has changed >>>>>> abort if pmd or pte has changed >>>>>> pte map and lock >>>>>> enable interrupt >>>>>> if abort >>>>>> free page >>>>>> abort >>>>>> ... >>>>>> } >>>>>> >>>>>> arch_fault_handler() >>>>>> { >>>>>> if (speculative_page_fault(&vma)) >>>>>> goto done >>>>>> again: >>>>>> lock(mmap_sem) >>>>>> vma = find_vma(); >>>>>> handle_pte_fault(vma); >>>>>> if retry >>>>>> unlock(mmap_sem) >>>>>> goto again; >>>>>> done: >>>>>> handle fault error >>>>>> } >>>>>> >>>>>> Support for THP is not done because when checking for the PMD, we can be >>>>>> confused by an in progress collapsing operation done by khugepaged. The >>>>>> issue is that pmd_none() could be true either if the PMD is not already >>>>>> populated or if the underlying PTE are in the way to be collapsed. So we >>>>>> cannot safely allocate a PMD if pmd_none() is true. >>>>>> >>>>>> This series add a new software performance event named 'speculative-faults' >>>>>> or 'spf'. It counts the number of successful page fault event handled >>>>>> speculatively. When recording 'faults,spf' events, the faults one is >>>>>> counting the total number of page fault events while 'spf' is only counting >>>>>> the part of the faults processed speculatively. >>>>>> >>>>>> There are some trace events introduced by this series. They allow >>>>>> identifying why the page faults were not processed speculatively. This >>>>>> doesn't take in account the faults generated by a monothreaded process >>>>>> which directly processed while holding the mmap_sem. This trace events are >>>>>> grouped in a system named 'pagefault', they are: >>>>>> - pagefault:spf_vma_changed : if the VMA has been changed in our back >>>>>> - pagefault:spf_vma_noanon : the vma->anon_vma field was not yet set. >>>>>> - pagefault:spf_vma_notsup : the VMA's type is not supported >>>>>> - pagefault:spf_vma_access : the VMA's access right are not respected >>>>>> - pagefault:spf_pmd_changed : the upper PMD pointer has changed in our >>>>>> back. >>>>>> >>>>>> To record all the related events, the easier is to run perf with the >>>>>> following arguments : >>>>>> $ perf stat -e 'faults,spf,pagefault:*' <command> >>>>>> >>>>>> There is also a dedicated vmstat counter showing the number of successful >>>>>> page fault handled speculatively. I can be seen this way: >>>>>> $ grep speculative_pgfault /proc/vmstat >>>>>> >>>>>> This series builds on top of v4.16-mmotm-2018-04-13-17-28 and is functional >>>>>> on x86, PowerPC and arm64. >>>>>> >>>>>> --------------------- >>>>>> Real Workload results >>>>>> >>>>>> As mentioned in previous email, we did non official runs using a "popular >>>>>> in memory multithreaded database product" on 176 cores SMT8 Power system >>>>>> which showed a 30% improvements in the number of transaction processed per >>>>>> second. This run has been done on the v6 series, but changes introduced in >>>>>> this new version should not impact the performance boost seen. >>>>>> >>>>>> Here are the perf data captured during 2 of these runs on top of the v8 >>>>>> series: >>>>>> vanilla spf >>>>>> faults 89.418 101.364 +13% >>>>>> spf n/a 97.989 >>>>>> >>>>>> With the SPF kernel, most of the page fault were processed in a speculative >>>>>> way. >>>>>> >>>>>> Ganesh Mahendran had backported the series on top of a 4.9 kernel and gave >>>>>> it a try on an android device. He reported that the application launch time >>>>>> was improved in average by 6%, and for large applications (~100 threads) by >>>>>> 20%. >>>>>> >>>>>> Here are the launch time Ganesh mesured on Android 8.0 on top of a Qcom >>>>>> MSM845 (8 cores) with 6GB (the less is better): >>>>>> >>>>>> Application 4.9 4.9+spf delta >>>>>> com.tencent.mm 416 389 -7% >>>>>> com.eg.android.AlipayGphone 1135 986 -13% >>>>>> com.tencent.mtt 455 454 0% >>>>>> com.qqgame.hlddz 1497 1409 -6% >>>>>> com.autonavi.minimap 711 701 -1% >>>>>> com.tencent.tmgp.sgame 788 748 -5% >>>>>> com.immomo.momo 501 487 -3% >>>>>> com.tencent.peng 2145 2112 -2% >>>>>> com.smile.gifmaker 491 461 -6% >>>>>> com.baidu.BaiduMap 479 366 -23% >>>>>> com.taobao.taobao 1341 1198 -11% >>>>>> com.baidu.searchbox 333 314 -6% >>>>>> com.tencent.mobileqq 394 384 -3% >>>>>> com.sina.weibo 907 906 0% >>>>>> com.youku.phone 816 731 -11% >>>>>> com.happyelements.AndroidAnimal.qq 763 717 -6% >>>>>> com.UCMobile 415 411 -1% >>>>>> com.tencent.tmgp.ak 1464 1431 -2% >>>>>> com.tencent.qqmusic 336 329 -2% >>>>>> com.sankuai.meituan 1661 1302 -22% >>>>>> com.netease.cloudmusic 1193 1200 1% >>>>>> air.tv.douyu.android 4257 4152 -2% >>>>>> >>>>>> ------------------ >>>>>> Benchmarks results >>>>>> >>>>>> Base kernel is v4.17.0-rc4-mm1 >>>>>> SPF is BASE + this series >>>>>> >>>>>> Kernbench: >>>>>> ---------- >>>>>> Here are the results on a 16 CPUs X86 guest using kernbench on a 4.15 >>>>>> kernel (kernel is build 5 times): >>>>>> >>>>>> Average Half load -j 8 >>>>>> Run (std deviation) >>>>>> BASE SPF >>>>>> Elapsed Time 1448.65 (5.72312) 1455.84 (4.84951) 0.50% >>>>>> User Time 10135.4 (30.3699) 10148.8 (31.1252) 0.13% >>>>>> System Time 900.47 (2.81131) 923.28 (7.52779) 2.53% >>>>>> Percent CPU 761.4 (1.14018) 760.2 (0.447214) -0.16% >>>>>> Context Switches 85380 (3419.52) 84748 (1904.44) -0.74% >>>>>> Sleeps 105064 (1240.96) 105074 (337.612) 0.01% >>>>>> >>>>>> Average Optimal load -j 16 >>>>>> Run (std deviation) >>>>>> BASE SPF >>>>>> Elapsed Time 920.528 (10.1212) 927.404 (8.91789) 0.75% >>>>>> User Time 11064.8 (981.142) 11085 (990.897) 0.18% >>>>>> System Time 979.904 (84.0615) 1001.14 (82.5523) 2.17% >>>>>> Percent CPU 1089.5 (345.894) 1086.1 (343.545) -0.31% >>>>>> Context Switches 159488 (78156.4) 158223 (77472.1) -0.79% >>>>>> Sleeps 110566 (5877.49) 110388 (5617.75) -0.16% >>>>>> >>>>>> >>>>>> During a run on the SPF, perf events were captured: >>>>>> Performance counter stats for '../kernbench -M': >>>>>> 526743764 faults >>>>>> 210 spf >>>>>> 3 pagefault:spf_vma_changed >>>>>> 0 pagefault:spf_vma_noanon >>>>>> 2278 pagefault:spf_vma_notsup >>>>>> 0 pagefault:spf_vma_access >>>>>> 0 pagefault:spf_pmd_changed >>>>>> >>>>>> Very few speculative page faults were recorded as most of the processes >>>>>> involved are monothreaded (sounds that on this architecture some threads >>>>>> were created during the kernel build processing). >>>>>> >>>>>> Here are the kerbench results on a 80 CPUs Power8 system: >>>>>> >>>>>> Average Half load -j 40 >>>>>> Run (std deviation) >>>>>> BASE SPF >>>>>> Elapsed Time 117.152 (0.774642) 117.166 (0.476057) 0.01% >>>>>> User Time 4478.52 (24.7688) 4479.76 (9.08555) 0.03% >>>>>> System Time 131.104 (0.720056) 134.04 (0.708414) 2.24% >>>>>> Percent CPU 3934 (19.7104) 3937.2 (19.0184) 0.08% >>>>>> Context Switches 92125.4 (576.787) 92581.6 (198.622) 0.50% >>>>>> Sleeps 317923 (652.499) 318469 (1255.59) 0.17% >>>>>> >>>>>> Average Optimal load -j 80 >>>>>> Run (std deviation) >>>>>> BASE SPF >>>>>> Elapsed Time 107.73 (0.632416) 107.31 (0.584936) -0.39% >>>>>> User Time 5869.86 (1466.72) 5871.71 (1467.27) 0.03% >>>>>> System Time 153.728 (23.8573) 157.153 (24.3704) 2.23% >>>>>> Percent CPU 5418.6 (1565.17) 5436.7 (1580.91) 0.33% >>>>>> Context Switches 223861 (138865) 225032 (139632) 0.52% >>>>>> Sleeps 330529 (13495.1) 332001 (14746.2) 0.45% >>>>>> >>>>>> During a run on the SPF, perf events were captured: >>>>>> Performance counter stats for '../kernbench -M': >>>>>> 116730856 faults >>>>>> 0 spf >>>>>> 3 pagefault:spf_vma_changed >>>>>> 0 pagefault:spf_vma_noanon >>>>>> 476 pagefault:spf_vma_notsup >>>>>> 0 pagefault:spf_vma_access >>>>>> 0 pagefault:spf_pmd_changed >>>>>> >>>>>> Most of the processes involved are monothreaded so SPF is not activated but >>>>>> there is no impact on the performance. >>>>>> >>>>>> Ebizzy: >>>>>> ------- >>>>>> The test is counting the number of records per second it can manage, the >>>>>> higher is the best. I run it like this 'ebizzy -mTt <nrcpus>'. To get >>>>>> consistent result I repeated the test 100 times and measure the average >>>>>> result. The number is the record processes per second, the higher is the >>>>>> best. >>>>>> >>>>>> BASE SPF delta >>>>>> 16 CPUs x86 VM 742.57 1490.24 100.69% >>>>>> 80 CPUs P8 node 13105.4 24174.23 84.46% >>>>>> >>>>>> Here are the performance counter read during a run on a 16 CPUs x86 VM: >>>>>> Performance counter stats for './ebizzy -mTt 16': >>>>>> 1706379 faults >>>>>> 1674599 spf >>>>>> 30588 pagefault:spf_vma_changed >>>>>> 0 pagefault:spf_vma_noanon >>>>>> 363 pagefault:spf_vma_notsup >>>>>> 0 pagefault:spf_vma_access >>>>>> 0 pagefault:spf_pmd_changed >>>>>> >>>>>> And the ones captured during a run on a 80 CPUs Power node: >>>>>> Performance counter stats for './ebizzy -mTt 80': >>>>>> 1874773 faults >>>>>> 1461153 spf >>>>>> 413293 pagefault:spf_vma_changed >>>>>> 0 pagefault:spf_vma_noanon >>>>>> 200 pagefault:spf_vma_notsup >>>>>> 0 pagefault:spf_vma_access >>>>>> 0 pagefault:spf_pmd_changed >>>>>> >>>>>> In ebizzy's case most of the page fault were handled in a speculative way, >>>>>> leading the ebizzy performance boost. >>>>>> >>>>>> ------------------ >>>>>> Changes since v10 (https://lkml.org/lkml/2018/4/17/572): >>>>>> - Accounted for all review feedbacks from Punit Agrawal, Ganesh Mahendran >>>>>> and Minchan Kim, hopefully. >>>>>> - Remove unneeded check on CONFIG_SPECULATIVE_PAGE_FAULT in >>>>>> __do_page_fault(). >>>>>> - Loop in pte_spinlock() and pte_map_lock() when pte try lock fails >>>>>> instead >>>>>> of aborting the speculative page fault handling. Dropping the now >>>>>> useless >>>>>> trace event pagefault:spf_pte_lock. >>>>>> - No more try to reuse the fetched VMA during the speculative page fault >>>>>> handling when retrying is needed. This adds a lot of complexity and >>>>>> additional tests done didn't show a significant performance improvement. >>>>>> - Convert IS_ENABLED(CONFIG_NUMA) back to #ifdef due to build error. >>>>>> >>>>>> [1] http://linux-kernel.2935.n7.nabble.com/RFC-PATCH-0-6-Another-go-at-speculative-page-faults-tt965642.html#none >>>>>> [2] https://patchwork.kernel.org/patch/9999687/ >>>>>> >>>>>> >>>>>> Laurent Dufour (20): >>>>>> mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT >>>>>> x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >>>>>> powerpc/mm: set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >>>>>> mm: introduce pte_spinlock for FAULT_FLAG_SPECULATIVE >>>>>> mm: make pte_unmap_same compatible with SPF >>>>>> mm: introduce INIT_VMA() >>>>>> mm: protect VMA modifications using VMA sequence count >>>>>> mm: protect mremap() against SPF hanlder >>>>>> mm: protect SPF handler against anon_vma changes >>>>>> mm: cache some VMA fields in the vm_fault structure >>>>>> mm/migrate: Pass vm_fault pointer to migrate_misplaced_page() >>>>>> mm: introduce __lru_cache_add_active_or_unevictable >>>>>> mm: introduce __vm_normal_page() >>>>>> mm: introduce __page_add_new_anon_rmap() >>>>>> mm: protect mm_rb tree with a rwlock >>>>>> mm: adding speculative page fault failure trace events >>>>>> perf: add a speculative page fault sw event >>>>>> perf tools: add support for the SPF perf event >>>>>> mm: add speculative page fault vmstats >>>>>> powerpc/mm: add speculative page fault >>>>>> >>>>>> Mahendran Ganesh (2): >>>>>> arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >>>>>> arm64/mm: add speculative page fault >>>>>> >>>>>> Peter Zijlstra (4): >>>>>> mm: prepare for FAULT_FLAG_SPECULATIVE >>>>>> mm: VMA sequence count >>>>>> mm: provide speculative fault infrastructure >>>>>> x86/mm: add speculative pagefault handling >>>>>> >>>>>> arch/arm64/Kconfig | 1 + >>>>>> arch/arm64/mm/fault.c | 12 + >>>>>> arch/powerpc/Kconfig | 1 + >>>>>> arch/powerpc/mm/fault.c | 16 + >>>>>> arch/x86/Kconfig | 1 + >>>>>> arch/x86/mm/fault.c | 27 +- >>>>>> fs/exec.c | 2 +- >>>>>> fs/proc/task_mmu.c | 5 +- >>>>>> fs/userfaultfd.c | 17 +- >>>>>> include/linux/hugetlb_inline.h | 2 +- >>>>>> include/linux/migrate.h | 4 +- >>>>>> include/linux/mm.h | 136 +++++++- >>>>>> include/linux/mm_types.h | 7 + >>>>>> include/linux/pagemap.h | 4 +- >>>>>> include/linux/rmap.h | 12 +- >>>>>> include/linux/swap.h | 10 +- >>>>>> include/linux/vm_event_item.h | 3 + >>>>>> include/trace/events/pagefault.h | 80 +++++ >>>>>> include/uapi/linux/perf_event.h | 1 + >>>>>> kernel/fork.c | 5 +- >>>>>> mm/Kconfig | 22 ++ >>>>>> mm/huge_memory.c | 6 +- >>>>>> mm/hugetlb.c | 2 + >>>>>> mm/init-mm.c | 3 + >>>>>> mm/internal.h | 20 ++ >>>>>> mm/khugepaged.c | 5 + >>>>>> mm/madvise.c | 6 +- >>>>>> mm/memory.c | 612 +++++++++++++++++++++++++++++----- >>>>>> mm/mempolicy.c | 51 ++- >>>>>> mm/migrate.c | 6 +- >>>>>> mm/mlock.c | 13 +- >>>>>> mm/mmap.c | 229 ++++++++++--- >>>>>> mm/mprotect.c | 4 +- >>>>>> mm/mremap.c | 13 + >>>>>> mm/nommu.c | 2 +- >>>>>> mm/rmap.c | 5 +- >>>>>> mm/swap.c | 6 +- >>>>>> mm/swap_state.c | 8 +- >>>>>> mm/vmstat.c | 5 +- >>>>>> tools/include/uapi/linux/perf_event.h | 1 + >>>>>> tools/perf/util/evsel.c | 1 + >>>>>> tools/perf/util/parse-events.c | 4 + >>>>>> tools/perf/util/parse-events.l | 1 + >>>>>> tools/perf/util/python.c | 1 + >>>>>> 44 files changed, 1161 insertions(+), 211 deletions(-) >>>>>> create mode 100644 include/trace/events/pagefault.h >>>>>> >>>>>> -- >>>>>> 2.7.4 >>>>>> >>>>>> >>>>> >>>> >>> >> >> >
