Messages in this thread | | | From | Eliezer Tamir <> | Subject | [PATCH v4 net-next 0/1] net: lls select poll support | Date | Mon, 24 Jun 2013 10:27:51 +0300 |
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David,
Here is a rework of the select/poll patch.
When select or poll are used on a lot of sockets the sysctl value needs to be set higher than 50. For 300 sockets a setting of 100 works for me. For 1000 sockets a setting of 200 works well but the gain is very small, probably not worth it.
I should mention that unlike the version we had in v9, with this version of the patch, LLS always performs better than no LLS.
In this version I split the sysctl entries into two. sysctl.net.core.low_latency_read for blocking socket reads. sysctl.net.core.low_latency_poll for select/poll.
The main reason we need two sysctl entries is that the values are different.
This also allows poll to busy poll only on some sockets. You set sysctl.net.core.low_latency_poll, but leave the read value 0. Then you use the socket option to enable SO_LL only on the sockets you would like to buys poll on.
Maybe what we really want is a cgroup that would allow settings per-process group.
-Eliezer
Change log: v4 - cleaned up formatting
v3 - split sysctl value into two separate ones, one for read and one for poll. - updated Documentation/sysctl/net.txt - fixed possible overflow (again) reported by Eric Dumazet. - poll/select loop optimizations by Eric Dumazet and Willem de Bruijn.
v2 - added POLL_LL flag, used to signal between the syscalls and sock_poll(). - add a separate ll_end_time() function to be used from poll. - slight reorder of sk_poll_ll so the timing primitives are not used when called from sock_poll(). - select/poll stop busy polling as soon as there is something to return to the user.
Change log from the original LLS patch series: v9 - better mask testing in sock_poll(), reported by Eric Dumazet.
v8 - split out udp and select/poll into separate patches. what used to be patch 2/5 is now three patches.
v5 - added simple poll/select support
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