From: Eliezer Tamir <eliezer.tamir@linux.intel.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Don Skidmore <donald.c.skidmore@intel.com>,
e1000-devel@lists.sourceforge.net,
Willem de Bruijn <willemb@google.com>,
Eric Dumazet <erdnetdev@gmail.com>,
Ben Hutchings <bhutchings@solarflare.com>, HPA <hpa@zytor.com>,
Eilon Greenstien <eilong@broadcom.com>,
Or Gerlitz <or.gerlitz@gmail.com>,
Amir Vadai <amirv@mellanox.com>,
Alex Rosenbaum <alexr@mellanox.com>,
Eliezer Tamir <eliezer@tamir.org.il>
Subject: Re: [PATCH v4 net-next] net: poll/select low latency socket support
Date: Fri, 28 Jun 2013 08:32:26 +0300 [thread overview]
Message-ID: <51CD1FEA.5020603@linux.intel.com> (raw)
In-Reply-To: <20130628044305.GQ6123@two.firstfloor.org>
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
prev parent reply other threads:[~2013-06-28 5:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-24 7:27 [PATCH v4 net-next 0/1] net: lls select poll support Eliezer Tamir
2013-06-24 7:28 ` [PATCH v4 net-next] net: poll/select low latency socket support Eliezer Tamir
2013-06-25 23:36 ` David Miller
2013-06-28 0:25 ` Cody P Schafer
2013-06-28 0:29 ` Cody P Schafer
2013-06-28 6:00 ` Eliezer Tamir
2013-06-28 4:43 ` Andi Kleen
2013-06-28 5:32 ` Eliezer Tamir [this message]
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