Re: [Cerowrt-devel] [Bloat] blip: a tool for seeing internet latency with javascript
This is indeed a cool hack. I was astonished for a moment, because it was a bedrock belief that you can't send pings from Javascript. And in fact, that is still true. Apenwarr's code sends short HTTP queries of the format shown below to each of two hosts: http://gstatic.com/generate_204 http://apenwarr.ca/blip/ The Blip tool shows ~60-70ms for the gstatic host, and ~130 msec for the latter. Ping times are ~52 msec and 125msec, respectively. These times seem to track response times by my eye (no serious analysis) to load both on my primary (bloated) router and CeroWrt. Still a cool hack. Rich - HTTP Request & Response for typical blip "ping" OPTIONS /generate_204 HTTP/1.1 Host: gstatic.com Connection: keep-alive Access-Control-Request-Method: GET Origin: http://gfblip.appspot.com User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31 Access-Control-Request-Headers: accept, origin, x-requested-with Accept: */* Referer: http://gfblip.appspot.com/ Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 HTTP/1.1 204 No Content Content-Length: 0 Content-Type: text/html; charset=UTF-8 Date: Sun, 28 Apr 2013 12:37:17 GMT Server: GFE/2.0 On Apr 26, 2013, at 7:04 PM, Dave Taht wrote: > Apenwarr has developed a really unique tool for seeing latency and > packet loss via javascript. I had no idea this was possible: > > http://apenwarr.ca/log/?m=201304#26 > > > > -- > Dave Täht > > Fixing bufferbloat with cerowrt: > http://www.teklibre.com/cerowrt/subscribe.html > ___ > Bloat mailing list > bl...@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat ___ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
Re: [Cerowrt-devel] [Bloat] blip: a tool for seeing internet latency with javascript
At home with latest cero, I'm getting results similar to Rich. I'm wondering how this will look tomorrow when I run it at company network, which is incredibly complex WAN path, proxied, with things like riverbed and checkpoint along the way. Maciej On Sun, Apr 28, 2013 at 4:56 PM, Rich Brown wrote: > This is indeed a cool hack. I was astonished for a moment, because it was > a bedrock belief that you can't send pings from Javascript. And in fact, > that is still true. > > Apenwarr's code sends short HTTP queries of the format shown below to each > of two hosts: > > http://gstatic.com/generate_204 > http://apenwarr.ca/blip/ > > The Blip tool shows ~60-70ms for the gstatic host, and ~130 msec for the > latter. Ping times are ~52 msec and 125msec, respectively. These times seem > to track response times by my eye (no serious analysis) to load both on my > primary (bloated) router and CeroWrt. > > Still a cool hack. > > Rich > > - > HTTP Request & Response for typical blip "ping" > > OPTIONS /generate_204 HTTP/1.1 > Host: gstatic.com > Connection: keep-alive > Access-Control-Request-Method: GET > Origin: http://gfblip.appspot.com > User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) > AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31 > Access-Control-Request-Headers: accept, origin, x-requested-with > Accept: */* > Referer: http://gfblip.appspot.com/ > Accept-Encoding: gzip,deflate,sdch > Accept-Language: en-US,en;q=0.8 > Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 > > HTTP/1.1 204 No Content > Content-Length: 0 > Content-Type: text/html; charset=UTF-8 > Date: Sun, 28 Apr 2013 12:37:17 GMT > Server: GFE/2.0 > > > On Apr 26, 2013, at 7:04 PM, Dave Taht wrote: > > > Apenwarr has developed a really unique tool for seeing latency and > > packet loss via javascript. I had no idea this was possible: > > > > http://apenwarr.ca/log/?m=201304#26 > > > > > > > > -- > > Dave Täht > > > > Fixing bufferbloat with cerowrt: > http://www.teklibre.com/cerowrt/subscribe.html > > ___ > > Bloat mailing list > > bl...@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/bloat > > ___ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel > ___ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
Re: [Cerowrt-devel] [Bloat] blip: a tool for seeing internet latency with javascript
Actually, using HTTP 1.1 GET that generates a single packet in each direction for a ping is quite reasonable. In fact, it is "better" for measuring actual path latencies, since ICMP pings *could* be discriminated against in a router along the way (in the "old days" people in the routing community suggested that ICMP should be diverted off of the "fast path" to avoid degrading the user experience). I've been using this technique to measure bufferbloat-induced delays on Phones and Android phones for quite a while. I have a couple of servers that use nginx "status" handlers to generate a short GET response without touching files as my "targets". Since it depends on HTTP 1.1's re-use of the underlying TCP connection for successive GET commands, it's a bit fragile. Javascript can be made to do a lot of performance testing - you can access both TCP and DNS protocols from the browser, so if you play cards right, you can cause single TCP exchanges and single UDP exchanges to happen with cooperative servers (web servers using HTTP 1.1 and DNS resolvers using uncacheable UDP name lookups). On Sunday, April 28, 2013 10:56am, "Rich Brown" said: > This is indeed a cool hack. I was astonished for a moment, because it was a > bedrock belief that you can't send pings from Javascript. And in fact, that is > still true. > > Apenwarr's code sends short HTTP queries of the format shown below to each of > two > hosts: > > http://gstatic.com/generate_204 > http://apenwarr.ca/blip/ > > The Blip tool shows ~60-70ms for the gstatic host, and ~130 msec for the > latter. > Ping times are ~52 msec and 125msec, respectively. These times seem to track > response times by my eye (no serious analysis) to load both on my primary > (bloated) router and CeroWrt. > > Still a cool hack. > > Rich > > - > HTTP Request & Response for typical blip "ping" > > OPTIONS /generate_204 HTTP/1.1 > Host: gstatic.com > Connection: keep-alive > Access-Control-Request-Method: GET > Origin: http://gfblip.appspot.com > User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.31 > (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31 > Access-Control-Request-Headers: accept, origin, x-requested-with > Accept: */* > Referer: http://gfblip.appspot.com/ > Accept-Encoding: gzip,deflate,sdch > Accept-Language: en-US,en;q=0.8 > Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 > > HTTP/1.1 204 No Content > Content-Length: 0 > Content-Type: text/html; charset=UTF-8 > Date: Sun, 28 Apr 2013 12:37:17 GMT > Server: GFE/2.0 > > > On Apr 26, 2013, at 7:04 PM, Dave Taht wrote: > > > Apenwarr has developed a really unique tool for seeing latency and > > packet loss via javascript. I had no idea this was possible: > > > > http://apenwarr.ca/log/?m=201304#26 > > > > > > > > -- > > Dave Täht > > > > Fixing bufferbloat with cerowrt: > http://www.teklibre.com/cerowrt/subscribe.html > > ___ > > Bloat mailing list > > bl...@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/bloat > > ___ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel > ___ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
Re: [Cerowrt-devel] [Codel] [Bloat] blip: a tool for seeing internet latency with javascript
On Sun, Apr 28, 2013 at 2:52 PM, wrote: > Actually, using HTTP 1.1 GET that generates a single packet in each > direction for a ping is quite reasonable. In fact, it is "better" for > measuring actual path latencies, since ICMP pings *could* be discriminated > against in a router along the way (in the "old days" people in the routing > community suggested that ICMP should be diverted off of the "fast path" to > avoid degrading the user experience). > Yes, using HTTP is good in this respect. I worked with the author of httping to get support for persistent connections 18 months or so ago. How to deal with proxies is one question, though one should mark the response uncachable. (unless the intent is to just test the path as far as the proxy. In practice, I've never seen signs of ICMP being put off the fast path in my testing; this doesn't mean it doesn't happen. > > > I've been using this technique to measure bufferbloat-induced delays on > Phones and Android phones for quite a while. I have a couple of servers > that use nginx "status" handlers to generate a short GET response without > touching files as my "targets". > > > > Since it depends on HTTP 1.1's re-use of the underlying TCP connection for > successive GET commands, it's a bit fragile. > I don't think this should be particularly fragile, unless you know something I don't. Jim > > > Javascript can be made to do a lot of performance testing - you can access > both TCP and DNS protocols from the browser, so if you play cards right, > you can cause single TCP exchanges and single UDP exchanges to happen with > cooperative servers (web servers using HTTP 1.1 and DNS resolvers using > uncacheable UDP name lookups). > > > > > > > > > > On Sunday, April 28, 2013 10:56am, "Rich Brown" > said: > > > This is indeed a cool hack. I was astonished for a moment, because it > was a > > bedrock belief that you can't send pings from Javascript. And in fact, > that is > > still true. > > > > Apenwarr's code sends short HTTP queries of the format shown below to > each of two > > hosts: > > > > http://gstatic.com/generate_204 > > http://apenwarr.ca/blip/ > > > > The Blip tool shows ~60-70ms for the gstatic host, and ~130 msec for the > latter. > > Ping times are ~52 msec and 125msec, respectively. These times seem to > track > > response times by my eye (no serious analysis) to load both on my primary > > (bloated) router and CeroWrt. > > > > Still a cool hack. > > > > Rich > > > > - > > HTTP Request & Response for typical blip "ping" > > > > OPTIONS /generate_204 HTTP/1.1 > > Host: gstatic.com > > Connection: keep-alive > > Access-Control-Request-Method: GET > > Origin: http://gfblip.appspot.com > > User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) > AppleWebKit/537.31 > > (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31 > > Access-Control-Request-Headers: accept, origin, x-requested-with > > Accept: */* > > Referer: http://gfblip.appspot.com/ > > Accept-Encoding: gzip,deflate,sdch > > Accept-Language: en-US,en;q=0.8 > > Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 > > > > HTTP/1.1 204 No Content > > Content-Length: 0 > > Content-Type: text/html; charset=UTF-8 > > Date: Sun, 28 Apr 2013 12:37:17 GMT > > Server: GFE/2.0 > > > > > > On Apr 26, 2013, at 7:04 PM, Dave Taht wrote: > > > > > Apenwarr has developed a really unique tool for seeing latency and > > > packet loss via javascript. I had no idea this was possible: > > > > > > http://apenwarr.ca/log/?m=201304#26 > > > > > > > > > > > > -- > > > Dave Täht > > > > > > Fixing bufferbloat with cerowrt: > > http://www.teklibre.com/cerowrt/subscribe.html > > > ___ > > > Bloat mailing list > > > bl...@lists.bufferbloat.net > > > https://lists.bufferbloat.net/listinfo/bloat > > > > ___ > > Cerowrt-devel mailing list > > Cerowrt-devel@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/cerowrt-devel > > > > > > > ___ > Codel mailing list > co...@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel > > ___ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
