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[76.81.105.82]) by smtp.gmail.com with ESMTPSA id l2sm4357696pjt.31.2020.01.23.20.18.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Jan 2020 20:18:17 -0800 (PST) Date: Thu, 23 Jan 2020 18:18:15 -1000 (HST) From: Jeff Roberson X-X-Sender: jroberson@desktop To: Gleb Smirnoff cc: Ryan Stone , src-committers , svn-src-all , svn-src-head Subject: Re: svn commit: r357051 - head/sys/dev/bge In-Reply-To: <20200124033243.GL1268@FreeBSD.org> Message-ID: References: <202001231636.00NGawrr080128@repo.freebsd.org> <20200123230546.GG1268@FreeBSD.org> <20200124012458.GI1268@FreeBSD.org> <20200124024356.GK1268@FreeBSD.org> <20200124033243.GL1268@FreeBSD.org> User-Agent: Alpine 2.21.9999 (BSF 287 2018-06-16) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-Rspamd-Queue-Id: 483m8q685Xz4TD6 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=jroberson-net.20150623.gappssmtp.com header.s=20150623 header.b=EFDD1gng; dmarc=none; spf=none (mx1.freebsd.org: domain of jroberson@jroberson.net has no SPF policy when checking 2607:f8b0:4864:20::643) smtp.mailfrom=jroberson@jroberson.net X-Spamd-Result: default: False [-2.71 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[jroberson-net.20150623.gappssmtp.com:s=20150623]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; IP_SCORE(-0.91)[ip: (-0.64), ipnet: 2607:f8b0::/32(-2.06), asn: 15169(-1.81), country: US(-0.05)]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[svn-src-all@freebsd.org]; DMARC_NA(0.00)[jroberson.net]; RCPT_COUNT_FIVE(0.00)[5]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[jroberson-net.20150623.gappssmtp.com:+]; RCVD_IN_DNSWL_NONE(0.00)[3.4.6.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; MID_RHS_NOT_FQDN(0.50)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FREEMAIL_CC(0.00)[gmail.com]; RCVD_TLS_ALL(0.00)[] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jan 2020 04:18:21 -0000 On Thu, 23 Jan 2020, Gleb Smirnoff wrote: > On Thu, Jan 23, 2020 at 05:09:14PM -1000, Jeff Roberson wrote: > J> While we don't have a policy strictly requiring reviews it is the norm to > J> have substantial changes socialized and reviewed. I appreciate the work > J> that you are doing but it likely should've been discussed somewhere > J> more publicly. I apologized if I missed it but I don't see reference to > J> anything. > > That was https://reviews.freebsd.org/D23242 Ok thank you. Can you tag commits so people can see the discussion? Was it in one I missed? When I'm committing a long patch series I include the link in all of them. Ryan, are you subscribed to @networking? > > J> Architecturally I am more concerned with the coarseness of net_epoch and > J> the duration of hold becoming a resource utilization problem in high > J> turn-over workloads. Like short connection tcp. Has anyone done > J> substantial testing here? epoch as it is today will hold every free > J> callback for a minimum of several clock ticks and a maximum of 2x the > J> duration of the longest epoch section time. With preemption, etc. this > J> could be 100s of ms of PCBs held. > > We also are concerned about that theoretically. Haven't yet seen effect > in practice, but our sessions are mostly longer living. First we have the > tunable to limit batching. Second, there are some ideas on how to improve > the garbage collector performance if it becomes an issue. I am often surprised at how much cpu time I see on linux spent in RCU free processing. Many of these things are written in such a way that everything is cache cold by the time you swing back around. So the callout walk is a giant cold linked list. Thanks, Jeff > > -- > Gleb Smirnoff >