Messages in this thread | | | Date | Fri, 28 Jun 2013 08:32:26 +0300 | From | Eliezer Tamir <> | Subject | Re: [PATCH v4 net-next] net: poll/select low latency socket support |
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On 28/06/2013 07:43, Andi Kleen wrote: >> @@ -400,6 +402,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) >> poll_table *wait; >> int retval, i, timed_out = 0; >> unsigned long slack = 0; >> + unsigned int ll_flag = POLL_LL; >> + u64 ll_time = ll_end_time(); > > So you're adding a sched_clock to every select call, even if it has > nothing to do with ll? > > That seems rather drastic. select can be performance critical.
would the following be acceptable?
unsigned int ll_flag = ll_poll_enabled(); // returns POLL_LL if on u64 ll_time = ll_flag ? ll_end_time() : 0;
and at the other side if (ll_flag && can_poll_ll(ll_end_time)) continue;
-Eliezer
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