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* Re: [dpdk-dev] [PATCH 5/8] event/dsw: avoid migration waves in large systems
@ 2020-03-09  7:17 Jerin Jacob Kollanukkaran
  2020-03-09  7:58 ` Mattias Rönnblom
  0 siblings, 1 reply; 5+ messages in thread
From: Jerin Jacob Kollanukkaran @ 2020-03-09  7:17 UTC (permalink / raw)
  To: Mattias Rönnblom; +Cc: dev, stefan.sundkvist, Ola.Liljedahl

> -----Original Message-----
> From: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> Sent: Monday, March 9, 2020 12:21 PM
> To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
> Cc: dev@dpdk.org; stefan.sundkvist@ericsson.com; Ola.Liljedahl@arm.com;
> Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> Subject:  [PATCH 5/8] event/dsw: avoid migration waves in large systems
> 
> ----------------------------------------------------------------------
> DSW limits the rate of migrations on a per-port basis. Hence, as the number of
> cores grows, so does the total migration capacity.
> 
> In high core-count systems, this allows for a situation where flows are migrated
> to a lightly loaded port which recently already received a number of new flows
> (from other ports). The processing load generated by these new flows may not
> yet be reflected in the lightly loaded port's load estimate. The result is that the
> previously lightly loaded port is now overloaded.
> 
> This patch adds a rough estimate of the size of the inbound migrations to a
> particular port, which can be factored into the migration logic, avoiding the
> above problem.
> 
> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> ---
> @@ -491,6 +502,9 @@ dsw_select_emigration_target(struct dsw_evdev *dsw,
>  	target_qfs[*targets_len] = *candidate_qf;
>  	(*targets_len)++;
> 
> +	rte_atomic32_add(&dsw->ports[candidate_port_id].immigration_load,
> +			 candidate_flow_load);

These are the full barriers in arm64 and PowerPC. 
Request to change the C11 mem model[1] with Load and acquire semantics
For better performance enhancement on non x86 machines.

drivers/event/opdl is already moved to C11 mem model.

[1]
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html


> +
>  	return true;

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [dpdk-dev] [PATCH 0/8] DSW performance and statistics improvements
@ 2020-03-09  6:50 Mattias Rönnblom
  2020-03-09  6:51 ` [dpdk-dev] [PATCH 5/8] event/dsw: avoid migration waves in large systems Mattias Rönnblom
  0 siblings, 1 reply; 5+ messages in thread
From: Mattias Rönnblom @ 2020-03-09  6:50 UTC (permalink / raw)
  To: jerinj; +Cc: dev, stefan.sundkvist, Ola.Liljedahl, Mattias Rönnblom

Performance and statistics improvements for the distributed software
(DSW) event device.

Mattias Rönnblom (8):
  event/dsw: reduce latency in low-load situations
  event/dsw: reduce max flows to speed up load balancing
  event/dsw: extend statistics
  event/dsw: improve migration mechanism
  event/dsw: avoid migration waves in large systems
  event/dsw: remove redundant control ring poll
  event/dsw: remove unnecessary read barrier
  event/dsw: add port busy cycles xstats

 drivers/event/dsw/dsw_evdev.c  |   1 +
 drivers/event/dsw/dsw_evdev.h  |  45 ++-
 drivers/event/dsw/dsw_event.c  | 602 ++++++++++++++++++++-------------
 drivers/event/dsw/dsw_xstats.c |  26 +-
 4 files changed, 425 insertions(+), 249 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-03-09  8:41 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-03-09  7:17 [dpdk-dev] [PATCH 5/8] event/dsw: avoid migration waves in large systems Jerin Jacob Kollanukkaran
2020-03-09  7:58 ` Mattias Rönnblom
2020-03-09  8:12   ` Jerin Jacob Kollanukkaran
2020-03-09  8:41     ` Mattias Rönnblom
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2020-03-09  6:50 [dpdk-dev] [PATCH 0/8] DSW performance and statistics improvements Mattias Rönnblom
2020-03-09  6:51 ` [dpdk-dev] [PATCH 5/8] event/dsw: avoid migration waves in large systems Mattias Rönnblom

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