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b=K3Zn69FGWwSiJtnA3FBjGGoXJSaQ410NJ80DjvSu6xdbeDuevOL9AACByNV9xTbWq o1J5l6e6+tCNtsnjE89KTNAGa4Lxg5PjNQ3TcF3VXEG21gwhgfJEATg3/IIt9tEc66 GJXmr+tN0rbXuqI4CE+7oAr1gZVH7BPL2W4HoyDbhMTuyHOZfNgC2AF5XZCMRCrQYA WKrgr+M8EgQ19bpl4A8CTpaNg4Qazlsnj8fxenfx9YSQdnaAph96gxTN7GzGa/3r9W IfKRxOxomD4OQCsbAf+EXogLaKsngv2775eNZwjfOvRUu0BspyMnzUWe72nWkaoNYR 0CXX9OuWyKmTA== Message-ID: Date: Tue, 20 Oct 2026 09:59:07 +0200 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [patch v5] mm: vmstat_kunit: add synthetic benchmark for mm stats To: David Rientjes , Andrew Morton Cc: Christoph Lameter , Vlastimil Babka , Mathieu Desnoyers , Sarthak Sharma , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <920ba123-077e-c42d-ebdf-a5effccf2073@google.com> <8b077a83-3f79-cbfa-0273-e086b0e51ae4@google.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <8b077a83-3f79-cbfa-0273-e086b0e51ae4@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 5213A40006 X-Stat-Signature: cqw81tdz1qqkhd31hymcfrg6iy3qegbw X-Rspam-User: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1792483152-973311 X-HE-Meta: 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 Xxi8dpY7 Zzp4zBNQc11+LPSgP8u/te8RSRK2SOgbeOoVmkTE46jH7Wkt8L/YyMnkjtVAN29GHyYhqj1ESKlK5cwz3bjrN5BF7BZZoFBvM2AZ/aBHrmSbqAuvg3iEU5ufYr0BRC1cr36GetFDCYNk+38jIRgjH+6CsDPQ+wvJoqo3vkULRDS1O5lxFOUvR1PrQSZpkgBW76Y99ZkOYSDuo43AsS0nsQZ0OE9S/TwXE15/fNV//cyFRUqise3d+NumB9A/Upot+yrb1H1cWXsjR06EBk9yvNbrTPKAglIu29tiZCldlQZtG9z9ynn5w+fuYG3+0gp/YaIAgzf+n9tcNdQO29PzimbJBEWN00MB9ks+YxvxqiGjTomIElH9UpGa0r/HfPJCIiq54RkAra8HuZyupZJjwWvhhcLWMsJ6FTOCGv6Pgt2DaApVZHo9rMeSV92FhdjVYGifgkHoHyV8wzsT+KJA+RiAQpw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/17/26 00:35, David Rientjes wrote: > On Fri, 9 Oct 2026, David Rientjes wrote: > >> From: Christoph Lameter >> >> Add a synthetic benchmark that can be used to measure performance of MM >> statistics. This is used to analyze any improvements or regressions in >> functions that are frequently used in hot code paths. >> >> This is the first of three tests that measure the execution times of >> critical MM functions anticipated to be used by developers to measure the >> impact of any core changes that would end up causing workload performance >> issues. Vmstats are embedded into MM hotpaths, so any regression can >> cause performance and scalability impact for users. Google has carried >> these tests internally and kept them updated since Christoph posted them >> back in 2009 for this purpose. >> >> This can also be used to detect regressions over time, from kernel >> version to kernel version, independent of development use cases. >> >> The test is run by KUnit or doing modprobe vmstat_kunit directly. >> >> Sample output: >> KTAP version 1 >> 1..1 >> KTAP version 1 >> # Subtest: vmstat >> # module: vmstat_kunit >> 1..3 >> # vmstat_test_inc_dec_zone_page_state: 10000 ops: inc_zone_page_state -> 8 cycles (4 ns/op), dec_zone_page_state -> 9 cycles (4 ns/op) >> ok 1 vmstat_test_inc_dec_zone_page_state >> # vmstat_test_interleaved_zone_page_state: 10000 ops: inc/dec pair -> 17 cycles (8 ns/op) >> ok 2 vmstat_test_interleaved_zone_page_state >> # vmstat_test_count_vm_event: 10000 ops: count_vm_event -> 4 cycles (2 ns/op) >> ok 3 vmstat_test_count_vm_event >> # vmstat: pass:3 fail:0 skip:0 total:3 >> # Totals: pass:3 fail:0 skip:0 total:3 >> ok 1 vmstat >> >> Assisted-by: Gemini:gemini-3.8-flash >> Signed-off-by: Christoph Lameter >> Signed-off-by: David Rientjes >> --- >> v5: >> - added dependency on CONFIG_VM_EVENT_COUNTERS >> - expanded commit description >> >> Once we're happy with this change, I'll apply the same treatment to the >> proposed pgalloc and slab tests. >> > > I've added the rationale for the change to the commit description as > primairly being used by developers to benchmark and monitor any > regressions in functions that are known to be super hot and impact > workload performance. > > This is the simplest of the three tests that Christoph provided back in > 2009, the others are pgalloc and slab tests, see > https://marc.info/?l=linux-mm&m=178547194364290 and > https://marc.info/?l=linux-mm&m=178547193264283 for those. Based on the > feedback to move to kunit, I forked this one off independently because it > was the simplest to address all the feedback and pave the way for the > other two to be upstreamed afterwards. > > Is this acceptable for merge? If we're happy with this, I'll move onto > the pgalloc and slab variants. Works for me. The tests are rather small and I see value in them. -- Cheers, David