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From: Robert Olsson <Robert.Olsson@data.slu.se>
To: Simon Kirby <sim@netnation.com>
Cc: Robert Olsson <Robert.Olsson@data.slu.se>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Eric Dumazet <dada1@cosmosbay.com>,
	netdev@oss.sgi.com
Subject: Re: Route cache performance
Date: Wed, 7 Sep 2005 16:45:03 +0200	[thread overview]
Message-ID: <17182.64751.340488.996748@robur.slu.se> (raw)
In-Reply-To: <20050906235700.GA31820@netnation.com>


Simon Kirby writes:

 > Woot!
 > 
 > Yes, this is the difference.  With the patch applied (ajust directly
 > freeing the dst_entry), everything balances easily, there are no
 > overflows, and the result of rt_may_expire() looks very reasonable.
 > (Yay!)
 >
 > So, this seems to be the culprit.  Is NAPI supposed to allow the
 > queued bh to run or should we just not be queuing this?

 Packet processing happens in RX_SOFIRQ. NAPI or non-NAPI is no difference
 with RCU deferred delete this should happen by the RCU-tasklet when 
 tasklets are run after the real SOFTIRQ's.

 There is a limit for RCU work... maxbatch it's set to 10  you could back 
 out the patch and try increase it 1000/10000 so we know this not prevent 
 the freeing of entries. 

 module_param(maxbatch, int, 0);  /* rcupdate.c */
 
 Also RCU clearly states that is should be used in read-mostly situations
 rDoS is outside this scope. Anyway it would be interesting to understand 
 what's going on.

 Cheers.
						--ro

 

  parent reply	other threads:[~2005-09-07 14:45 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-15 21:38 Route cache performance Simon Kirby
2005-08-16  2:23 ` Eric Dumazet
2005-08-23 19:08   ` Simon Kirby
2005-08-23 19:56     ` Robert Olsson
2005-08-24  0:01       ` Simon Kirby
2005-08-24  3:50         ` Robert Olsson
2005-08-25 18:11         ` Simon Kirby
2005-08-25 20:05           ` Alexey Kuznetsov
2005-08-25 21:22             ` Simon Kirby
2005-08-26 11:55               ` Alexey Kuznetsov
2005-08-26 19:49                 ` Robert Olsson
2005-09-06 23:57                   ` Simon Kirby
2005-09-07  1:19                     ` Alexey Kuznetsov
2005-09-07 15:03                       ` Robert Olsson
2005-09-07 16:55                         ` Simon Kirby
2005-09-07 17:21                           ` Robert Olsson
2005-09-07 14:45                     ` Robert Olsson [this message]
2005-09-07 16:28                       ` Simon Kirby
2005-09-07 16:49                         ` Robert Olsson
2005-09-07 16:57                           ` Simon Kirby
2005-09-07 19:59                         ` Alexey Kuznetsov
2005-09-13 22:14                           ` Simon Kirby
2005-09-14  8:04                             ` Robert Olsson
2005-09-17  0:28                               ` Simon Kirby
2005-09-17  9:04                                 ` Martin Josefsson
2005-09-17 15:17                                 ` jamal
2005-09-15 21:04                             ` Alexey Kuznetsov
2005-09-15 21:30                               ` Robert Olsson
2005-09-15 22:21                                 ` Alexey Kuznetsov
2005-09-16 12:18                                   ` Robert Olsson
2005-09-16 19:04                                     ` Alexey Kuznetsov
2005-09-16 19:22                                       ` Ben Greear
2005-09-16 19:57                                       ` Robert Olsson
  -- strict thread matches above, loose matches on Subject: below --
2005-08-24 16:06 Simon Kirby
     [not found] <20050301220743.GF2554@netnation.com>
     [not found] ` <16940.9990.975632.115834@robur.slu.se>
2005-03-09  1:45   ` Simon Kirby
2005-03-09 12:05     ` Robert Olsson

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