On Wed, 13 Feb 2019 08:51:01 -0800 Stephen Hemminger <step...@networkplumber.org> wrote:
> On Wed, 13 Feb 2019 09:37:11 +0100 > Stefano Brivio <sbri...@redhat.com> wrote: > > > On Tue, 12 Feb 2019 16:42:04 -0800 > > Eric Dumazet <eric.duma...@gmail.com> wrote: > > > > > I do not get it. > > > > > > "ss -emoi " uses almost 1KB per socket. > > > > > > 10,000,000 sockets -> we need about 10GB of memory ??? > > > > > > This is a serious regression. > > > > I guess this is rather subjective: the worst case I considered back then > > was the output of 'ss -tei0' (less than 500 bytes) for one million > > sockets, which gives 500M of memory, which should in turn be fine on a > > machine handling one million sockets. > > > > Now, if 'ss -emoi' on 10 million sockets is an actual use case (out of > > curiosity: how are you going to process that output? Would JSON help?), > > I see two easy options to solve this: > > > > 1. flush the output every time we reach a given buffer size (1M > > perhaps). This might make the resulting blocks slightly unaligned, > > with occasional loss of readability on lines occurring every 1k to > > 10k sockets approximately, even though after 1k sockets column sizes > > won't change much (it looks anyway better than the original), and I > > don't expect anybody to actually scroll that output > > > > 2. add a switch for unbuffered output, but then you need to remember to > > pass it manually, and the whole output would be as bad as the > > original in case you need the switch. > > > > I'd rather go with 1., it's easy to implement (we already have partial > > flushing with '--events') and it looks like a good compromise on > > usability. Thoughts? > > > I agree with eric. The benefits of buffering are not worth it. > Let's just choose a reasonable field width, if something is too big, columns > won't line up > which i snot a big deal. That's how it was before, and we couldn't even get fields aligned with TCP and UDP sockets in a 80 columns wide terminal. See examples at: https://patchwork.ozlabs.org/cover/847301/. I tried, but I think it's impossible to find a "reasonable" field width, especially when you mix a number of socket types. > Unless you come up with a better solution, I am going to revert this. That's why I asked for feedback about my proposals 1. and 2. above. I'll go for 1. then. -- Stefano
