{"id":83511,"date":"2020-06-01T07:42:29","date_gmt":"2020-06-01T05:42:29","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/proizvoditelnost-raspberry-pi-dobavlyaem-zram-i-izmenyaem-parametry-yadra"},"modified":"2020-06-01T07:42:29","modified_gmt":"2020-06-01T05:42:29","slug":"proizvoditelnost-raspberry-pi-dobavlyaem-zram-i-izmenyaem-parametry-yadra","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/proizvoditelnost-raspberry-pi-dobavlyaem-zram-i-izmenyaem-parametry-yadra","title":{"rendered":"V\u00fdkon Raspberry Pi: p\u0159id\u00e1me ZRAM a m\u011bn\u00edme parametry j\u00e1dra","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

P\u0159ed n\u011bkolika t\u00fddny jsem publikoval p\u0159ehled Pinebook Pro<\/a><\/noindex>. Proto\u017ee Raspberry Pi 4 je tak\u00e9 zalo\u017een\u00e1 na ARM, n\u011bkter\u00e9 z optimalizac\u00ed zm\u00edn\u011bn\u00fdch v p\u0159edchoz\u00edm \u010dl\u00e1nku j\u00ed \u00fapln\u011b vyhovuj\u00ed. R\u00e1d bych se pod\u011blil o tyto tipy a zjistil, zda se u v\u00e1s projev\u00ed podobn\u00e1 zlep\u0161en\u00ed v\u00fdkonu.<\/p>\n

Po instalaci Raspberry Pi do m\u00e9 dom\u00e1c\u00ed serverovny<\/a><\/noindex> jsem si v\u0161iml, \u017ee v momentech nedostatku opera\u010dn\u00ed pam\u011bti se stala velmi nevyzpytatelnou a dokonce zamrzala. Abych tento probl\u00e9m vy\u0159e\u0161il, p\u0159idal jsem ZRAM a provedl n\u011bkolik zm\u011bn v nastaven\u00ed j\u00e1dra.
\n<\/a><\/noindex><\/p>\n

Aktivace ZRAM na Raspberry Pi<\/h1>\n

\n\"V\u00fdkon
\n
\nZRAM<\/a><\/noindex> vytv\u00e1\u0159\u00ed v opera\u010dn\u00ed pam\u011bti blokov\u00e9 \u00falo\u017ei\u0161t\u011b pojmenov\u00e1no \/dev\/zram0 (nebo 1, 2, 3 atd.). Str\u00e1nky zapsan\u00e9 sem jsou komprimov\u00e1ny a uchov\u00e1v\u00e1ny v pam\u011bti. To umo\u017e\u0148uje velmi rychl\u00fd vstup-v\u00fdstup a tak\u00e9 uvol\u0148uje pam\u011b\u0165 d\u00edky kompresi.<\/p>\n

Raspberry Pi 4 je dod\u00e1van\u00e1 s 1, 2, 4 nebo 8 GB opera\u010dn\u00ed pam\u011bti. Pou\u017eiji model s 1 GB, proto si p\u0159izp\u016fsobte n\u00e1vod podle sv\u00e9ho modelu. S 1 GB bude v\u00fdchoz\u00ed swapov\u00fd soubor (pomal\u00fd!) pou\u017e\u00edv\u00e1n m\u00e9n\u011b \u010dasto. Pou\u017eil jsem tento skript zram-swap<\/a><\/noindex> pro instalaci a automatizovan\u00e9 nastaven\u00ed.<\/p>\n

Pokyny najdete v repozit\u00e1\u0159i na odkazu v\u00fd\u0161e. Instalace:<\/p>\n

git clone https:\/\/github.com\/foundObjects\/zram-swap.git\ncd zram-swap && sudo .\/install.sh<\/code><\/pre>\n
\nPokud chcete upravit konfiguraci:<\/p>\n
vi \/etc\/default\/zram-swap<\/code><\/pre>\n
\nKrom\u011b toho lze ZRAM aktivovat instalac\u00ed zram-tools<\/code>. Pokud pou\u017e\u00edv\u00e1te tuto metodu, nezapome\u0148te upravit konfiguraci<\/b> v souboru \/etc\/default\/zramswap<\/code>, a nastavte p\u0159ibli\u017en\u011b 1 GB ZRAM:<\/p>\n
sudo apt install zram-tools<\/code><\/pre>\n
\nPo instalaci m\u016f\u017eete zobrazit statistiky \u00falo\u017ei\u0161t\u011b ZRAM n\u00e1sleduj\u00edc\u00edm p\u0159\u00edkazem:<\/p>\n
sudo cat \/proc\/swaps\nFilename\t\t\t\tType\t\tSize\tUsed\tPriority\n\/var\/swap                               file\t\t102396\t0\t-2\n\/dev\/zram0                              partition\t1185368\t265472\t5\npi@raspberrypi:~ $<\/code><\/pre>\n
<\/p>\n
P\u0159id\u00e1v\u00e1me parametry j\u00e1dra pro lep\u0161\u00ed vyu\u017eit\u00ed ZRAM<\/h1>\n
\nTe\u010f oprav\u00edme chov\u00e1n\u00ed syst\u00e9mu, kdy\u017e Raspberry Pi p\u0159ech\u00e1z\u00ed na swap v posledn\u00edm moment\u011b, co\u017e \u010dasto vede k zamrz\u00e1n\u00ed. P\u0159id\u00e1me n\u011bkolik \u0159\u00e1dk\u016f do souboru \/etc\/sysctl.conf<\/b> a restartujeme.<\/p>\n
Tyto \u0159\u00e1dky 1) odlo\u017e\u00ed nevyhnuteln\u00e9 vy\u010derp\u00e1n\u00ed pam\u011bti<\/b>, zv\u00fd\u0161en\u00edm tlaku na pam\u011b\u0165ovou cache j\u00e1dra a 2) d\u0159\u00edve za\u010dnou p\u0159ipravovat vy\u010derp\u00e1n\u00ed pam\u011bti<\/b>, p\u0159edem iniciov\u00e1n\u00edm swapu. Ale to bude mnohem efektivn\u011bj\u0161\u00ed swap komprimovan\u00e9 pam\u011bti p\u0159es ZRAM!<\/p>\n
Zde jsou \u0159\u00e1dky, kter\u00e9 je t\u0159eba p\u0159idat na konec souboru \/etc\/sysctl.conf<\/b>:<\/p>\n
vm.vfs_cache_pressure=500\nvm.swappiness=100\nvm.dirty_background_ratio=1\nvm.dirty_ratio=50<\/code><\/pre>\n
\nPot\u00e9 restartujeme syst\u00e9m nebo aktivujeme \u00fapravy n\u00e1sleduj\u00edc\u00edm p\u0159\u00edkazem:<\/p>\n
sudo sysctl --system<\/code><\/pre>\n
\nvm.vfs_cache_pressure=500<\/b> zvy\u0161uje tlak na cache, co\u017e zvy\u0161uje tendenci j\u00e1dra k rekultivaci pam\u011bti pou\u017e\u00edvan\u00e9 pro cachov\u00e1n\u00ed objekt\u016f adres\u00e1\u0159\u016f a index\u016f. Budete pou\u017e\u00edvat m\u00e9n\u011b pam\u011bti po del\u0161\u00ed dobu. N\u00e1hl\u00fd pokles v\u00fdkonu se kompenzuje d\u0159\u00edv\u011bj\u0161\u00edm swappov\u00e1n\u00edm.<\/p>\n
vm.swappiness=100<\/b> zvy\u0161uje parametr, jak agresivn\u011b j\u00e1dro bude swappovat str\u00e1nky pam\u011bti, proto\u017ee nejprve pou\u017e\u00edv\u00e1me ZRAM.<\/p>\n
vm.dirty_background_ratio=1 & vm.dirty_ratio=50<\/b> \u2014 pozad\u00ed procesy za\u010dnou zapisovat hned p\u0159i dosa\u017een\u00ed limitu 1%, ale syst\u00e9m nebude nucen\u011b prov\u00e1d\u011bt synchronn\u00ed vstup\/v\u00fdstup, dokud nedos\u00e1hne dirty_ratio 50%.<\/p>\n
Tyto \u010dty\u0159i \u0159\u00e1dky (pou\u017eit\u00e9 se ZRAM) pomohou zlep\u0161it v\u00fdkon, pokud m\u00e1te nevyhnuteln\u011b<\/u> nedostatek opera\u010dn\u00ed pam\u011bti a za\u010d\u00edn\u00e1 p\u0159echod na swap, jako u m\u011b. S v\u011bdom\u00edm t\u00e9to skute\u010dnosti a tak\u00e9 se zohledn\u011bn\u00edm trojn\u00e1sobn\u00e9ho zhutn\u011bn\u00ed pam\u011bti v ZRAM je lep\u0161\u00ed za\u010d\u00edt s t\u00edmto swappov\u00e1n\u00edm d\u0159\u00edve.<\/p>\n
Tlak na cache pom\u00e1h\u00e1, proto\u017ee vlastn\u011b \u0159\u00edk\u00e1me j\u00e1dru: \u201eHele, nem\u00e1m \u017e\u00e1dnou dal\u0161\u00ed pam\u011b\u0165, kterou bych pou\u017eil na cache, tak\u017ee se pros\u00edm co nejd\u0159\u00edve zbav toho, a uchovej pouze nej\u010dast\u011bji pou\u017e\u00edvan\u00e1\/nejd\u016fle\u017eit\u011bj\u0161\u00ed data.\u201c<\/p>\n
I kdy\u017e se sn\u00ed\u017e\u00ed cachov\u00e1n\u00ed, pokud s \u010dasem bude v\u011bt\u0161ina dostupn\u00e9 pam\u011bti obsazena, j\u00e1dro za\u010dne oportunisticky swapovat mnohem d\u0159\u00edve, tak\u017ee procesor (zhutn\u011bn\u00ed) a vstup\/v\u00fdstup swapov\u00e1n\u00ed nebudou \u010dekat na posledn\u00ed chv\u00edli a zapoj\u00ed v\u0161echny zdroje najednou, kdy\u017e u\u017e bude p\u0159\u00edli\u0161 pozd\u011b. ZRAM pou\u017e\u00edv\u00e1 trochu CPU na zhutn\u011bn\u00ed, ale ve v\u011bt\u0161in\u011b syst\u00e9m\u016f s mal\u00fdm objemem pam\u011bti to m\u00e1 mnohem men\u0161\u00ed vliv na v\u00fdkon ne\u017e swap bez ZRAM.<\/p>\n
Na z\u00e1v\u011br<\/h1>\n
\nPod\u00edvejme se je\u0161t\u011b jednou na v\u00fdsledek:<\/p>\n
pi@raspberrypi:~ $ free -h\ntotal used free shared buff\/cache available\nMem: 926Mi 471Mi 68Mi 168Mi 385Mi 232Mi\nSwap: 1.2Gi 258Mi 999Mi\n\npi@raspberrypi:~ $ sudo cat \/proc\/swaps \nFilename Type Size Used Priority\n\/var\/swap file 102396 0 -2\n\/dev\/zram0 partition 1185368 264448 5<\/code><\/pre>\n
\n264448 v ZRAM \u2014 to je t\u00e9m\u011b\u0159 jeden gigabyte neskomprimovan\u00fdch dat. V\u0161echno \u0161lo do ZRAM a nic se nedostalo do mnohem pomalej\u0161\u00edho swapovac\u00edho souboru. Vyzkou\u0161ejte si tato nastaven\u00ed, funguj\u00ed na v\u0161ech modelech Raspberry Pi. M\u016fj nefunk\u010dn\u00ed a zamrzaj\u00edc\u00ed syst\u00e9m se stal funk\u010dn\u00edm a stabiln\u00edm.<\/p>\n
V bl\u00edzk\u00e9 budoucnosti douf\u00e1m, \u017ee se mi poda\u0159\u00ed pokra\u010dovat a aktualizovat tento \u010dl\u00e1nek s n\u011bkter\u00fdmi v\u00fdsledky testov\u00e1n\u00ed syst\u00e9mu p\u0159ed a po instalaci ZRAM. Te\u010f na to prost\u011b nem\u00e1m \u010das. Zat\u00edm nev\u00e1hejte prov\u00e1d\u011bt sv\u00e9 vlastn\u00ed testy a dejte v\u011bd\u011bt v koment\u00e1\u0159\u00edch. Raspberry Pi 4 je prost\u011b zv\u00ed\u0159e s takov\u00fdmi nastaven\u00edmi. U\u017eijte si to!<\/p>\n
K t\u00e9matu:<\/b><\/p>\n