On Wed, Oct 11, 2023 at 8:49 PM Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> wrote: > > > > > -----Original Message----- > > From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> > > Sent: Tuesday, October 10, 2023 10:16 PM > > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > > Cc: Yuchung Cheng <ycheng@xxxxxxxxxx>; linux-hyperv@xxxxxxxxxxxxxxx; > > netdev@xxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>; > > davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; > > pabeni@xxxxxxxxxx; corbet@xxxxxxx; dsahern@xxxxxxxxxx; > > ncardwell@xxxxxxxxxx; kuniyu@xxxxxxxxxx; morleyd@xxxxxxxxxx; > > mfreemon@xxxxxxxxxxxxxx; mubashirq@xxxxxxxxxx; linux- > > doc@xxxxxxxxxxxxxxx; weiwan@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH net-next,v2] tcp: Set pingpong threshold via sysctl > > > > On Tue, 10 Oct 2023 22:59:49 +0000 > > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> wrote: > > > > > > > If this an application specific optimization, it should be in a socket option > > > > > rather than system wide via sysctl. > > > > Initially I had a similar comment but later decided a sysctl could > > > > still be useful if > > > > 1) the entire host (e.g. virtual machine) is dedicated to that application > > > > 2) that application is difficult to change > > > > > > Yes, the customer actually wants a global setting. But as suggested by Neal, > > > I changed it to be per-namespace to match other TCP tunables. > > > > Like congestion control choice, it could be both a sysctl and a socket option. > > The reason is that delayed ack is already controlled by socket options. > > I see. I am updating the doc and variable location for this sysctl tunable patch > as suggested by the reviewers, and will resubmit it. > > I will also work on a separate patch for the setsockopt option. > > I am not sure about adding a socket option, and finding room in the socket structure. See our recent effort reshuffling fields in tcp socket for better performance (stalled at this time). I would rather experiment first with a sysctl.
