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[209.85.167.174]) by smtp.gmail.com with ESMTPSA id k26sm3321270oiw.34.2020.01.13.01.13.42 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Jan 2020 01:13:42 -0800 (PST) Received: by mail-oi1-f174.google.com with SMTP id k4so7605869oik.2 for ; Mon, 13 Jan 2020 01:13:42 -0800 (PST) X-Received: by 2002:aca:2b0a:: with SMTP id i10mr12159430oik.137.1578906822019; Mon, 13 Jan 2020 01:13:42 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Reply-To: cem@freebsd.org From: Conrad Meyer Date: Mon, 13 Jan 2020 01:13:31 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: adding some smartness in file cache To: Wojciech Puchar Cc: "freebsd-hackers@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 47x7Dl5ddHz4D6J X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of csecem@gmail.com designates 209.85.210.51 as permitted sender) smtp.mailfrom=csecem@gmail.com X-Spamd-Result: default: False [-3.22 / 15.00]; TO_DN_EQ_ADDR_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; HAS_REPLYTO(0.00)[cem@freebsd.org]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17:c]; RWL_MAILSPIKE_GOOD(0.00)[51.210.85.209.rep.mailspike.net : 127.0.0.18]; REPLYTO_ADDR_EQ_FROM(0.00)[]; RCVD_COUNT_THREE(0.00)[4]; RCPT_COUNT_TWO(0.00)[2]; FORGED_SENDER(0.30)[cem@freebsd.org,csecem@gmail.com]; MIME_TRACE(0.00)[0:+]; R_DKIM_NA(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; TAGGED_FROM(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_NEQ_ENVFROM(0.00)[cem@freebsd.org,csecem@gmail.com]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; DMARC_NA(0.00)[freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[51.210.85.209.list.dnswl.org : 127.0.5.0]; IP_SCORE(-1.22)[ip: (-1.10), ipnet: 209.85.128.0/17(-3.09), asn: 15169(-1.84), country: US(-0.05)]; RCVD_TLS_ALL(0.00)[] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Jan 2020 09:13:44 -0000 Consider modifying your linear scan programs to use posix_fadvise(2) POSIX_FADV_DONTNEED and/or POSIX_FADV_NOREUSE. You're right that we could be a bit more clever than straight LRU for eviction (if we are not already), such as incorporating some hybrid scoring using MRU/LFU/RR-like eviction policies. Your proposal is an extremely specific MRU heuristic. On Sun, Jan 12, 2020 at 4:21 AM Wojciech Puchar wrote: > > FreeBSD uses unified cache which is generally great but have some > disadventages. > > One common is case of linear reading or writing of large files. > This wipes out other things from memory very quickly. > > Can cache be made to drop every full block (MAXPHYS) from cache instantly > after is fully read by user program or is wrote to disk. > > This way memory would be much better utilized in caching small I/O. > > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"