This requires my win_scale_factor to at least be set to 6 so that the counter is able to mathematically reach this value. So, I chose 3125000 as my upper limit for both my sendspace and recvspace parameters. That is equivalent to 25,000,000 bits or 3,125,000 Bytes on the wire during any 1 round trip interval. I have a 1Gbps connection with an average round trip latency of about 25 milliseconds. I arrived at my value using my Bandwidth-Delay Product. Please refer to my previous posts for the explanation on how you can calculate this. You will see less throughput oscillation and more consistency from TCP. The less ACKs you have to wait for or send, the faster data will move on the wire. This means how many packets can you send or receive before you have to wait for an acknowledgement or ACK packet from the receiver or before you send an ACK packet back to the sender. The TCP sendspace and recvspace parameters control the maximum TCP window size the system will allow sending from the machine or receiving to the machine. So, using the upper end at 7 milliseconds, I come up with about 60 packets. This is anywhere from 4 to 7 milliseconds for services local to the DFW area. So, I decided to use my best case latency, instead of my general average, as the basis for my calculation. This is especially true at the moment during this home quarantine period where we have myself and my wife working from home on VPN and 4 kids all using Google classroom and Zoom and FaceTime and YouTube on a continual basis. Arguably, I don’t really need to be consuming all of my link bandwidth when I have quite a few other people and devices also using my network. So, taking the line rate at 1000Mbps or 1000 x 10 6 x 25 milliseconds or 0.025 seconds / 8 bits per byte / 1448 bytes per packet x 10%, I came up with roughly 215 packets. I calculated this by figuring my Bandwidth-Delay Product and taking 10% of that value divided by the max MSS of 1448 bytes to get rough packet count. This allows my system to use up to 10% of my bandwidth during TCP ramp up. In order to more quickly overcome TCP slowstart, I have bumped this up quite a bit. It depends on you link speed and latency. This number is a little more complicated to arrive at.
Macos sierra performance full#
The slowstart_flightsize parameter governs how fast your TCP stack can ramp up to using your full TCP window or link bandwidth outside of your local network. As a client machine, there is no reason you need to be friendly to remote systems. This is a sort of stealth mechanism but also reduces unnecessary overhead.
Macos sierra performance mac#
This will prevent your Mac from sending RST packets for closed ports. You should set your TCP blackhole setting to a value of 2. If you experience any sort of connection hanging, you may want to disable this feature by setting it to 0. The large majority of users will not be impacted by this behavior on 100Meg or 1Gig interfaces. 10Gig), it appeared that the delayed_ack feature presented performance issues. In the comments on my previous post, a contributor noted that on interfaces above 1Gig (e.g. Apple used to have an issue on higher speed interfaces but they may have overcome this problem. This effectively enables the Nagle algorithm but prevents the unacknowledged runt packet problem causing an ACK deadlock which can unnecessarily pause transfers and cause significant delays. Apple is now defaulting the setting for Delayed ACK (_ack) to 3 which is for Auto-Detect. This is good for any Gigabit interface to prevent the TCP wrap issue. Other than that, there are only a handful of other kernel options remaining that can help you get more out of your Internet connection.Īpple appears to be setting the MSL () Maximum Segment Life to 15000 or 15 seconds as a default. Apple is STILL defaulting the MSS to 512 Bytes! I am still recommending to set your MSS () to 1448. This automatically adds 12 Bytes of overhead to the MSS.
It appears that the option to enable RFC1323 High Performance TCP Options is no longer an option and is now enabled as a default setting.
Macos sierra performance pro#
So, without further ado, here is what I have discovered so far with macOS Mojave 10.14 running on a MacBook Pro 15″ 2019. The information in this article is targeted to the average home MacBook user and does not really address much of the high end power user needs like 10Gig networking. So, I may be a little slow but I eventually get around to upgrading and sifting through the changes. It seems that Apple keeps changing old default settings, removing options, and adding new parameters with each new OS release. Please refer to these previous posts for further explanation and detail on the specific settings beyond what I’ve included here. So, I guess a few people have found my analysis useful and worthwhile.
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