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From: "naamax.meir" <naamax.meir@linux.intel.com>
To: Vinicius Costa Gomes <vinicius.gomes@intel.com>,
	intel-wired-lan@lists.osuosl.org
Cc: vladimir.oltean@nxp.com, kurt@linutronix.de, anthony.l.nguyen@intel.com
Subject: Re: [Intel-wired-lan] [PATCH iwl-net v4 3/4] igc: Retrieve TX timestamp during interrupt handling
Date: Tue, 20 Jun 2023 22:02:46 +0300	[thread overview]
Message-ID: <077e8567-0e45-8afe-f68d-d87a72be703f@linux.intel.com> (raw)
In-Reply-To: <20230607213232.875138-4-vinicius.gomes@intel.com>

On 6/8/2023 00:32, Vinicius Costa Gomes wrote:
> When the interrupt is handled, the TXTT_0 bit in the TSYNCTXCTL
> register should already be set and the timestamp value already loaded
> in the appropriate register.
> 
> This simplifies the handling, and reduces the latency for retrieving
> the TX timestamp, which increase the amount of TX timestamps that can
> be handled in a given time period.
> 
> As the "work" function doesn't run in a workqueue anymore, rename it
> to something more sensible, a event handler.
> 
> Using ntpperf[1] we can see the following performance improvements:
> 
> Before:
> 
> $ sudo ./ntpperf -i enp3s0 -m 10:22:22:22:22:21 -d 192.168.1.3 -s 172.18.0.0/16 -I -H -o -37
>                 |          responses            |     TX timestamp offset (ns)
> rate   clients |  lost invalid   basic  xleave |    min    mean     max stddev
> 1000       100   0.00%   0.00%   0.00% 100.00%      -56      +9     +52     19
> 1500       150   0.00%   0.00%   0.00% 100.00%      -40     +30     +75     22
> 2250       225   0.00%   0.00%   0.00% 100.00%      -11     +29     +72     15
> 3375       337   0.00%   0.00%   0.00% 100.00%      -18     +40     +88     22
> 5062       506   0.00%   0.00%   0.00% 100.00%      -19     +23     +77     15
> 7593       759   0.00%   0.00%   0.00% 100.00%       +7     +47   +5168     43
> 11389     1138   0.00%   0.00%   0.00% 100.00%      -11     +41   +5240     39
> 17083     1708   0.00%   0.00%   0.00% 100.00%      +19     +60   +5288     50
> 25624     2562   0.00%   0.00%   0.00% 100.00%       +1     +56   +5368     58
> 38436     3843   0.00%   0.00%   0.00% 100.00%      -84     +12   +8847     66
> 57654     5765   0.00%   0.00% 100.00%   0.00%
> 86481     8648   0.00%   0.00% 100.00%   0.00%
> 129721   12972   0.00%   0.00% 100.00%   0.00%
> 194581   16384   0.00%   0.00% 100.00%   0.00%
> 291871   16384  27.35%   0.00%  72.65%   0.00%
> 437806   16384  50.05%   0.00%  49.95%   0.00%
> 
> After:
> 
> $ sudo ./ntpperf -i enp3s0 -m 10:22:22:22:22:21 -d 192.168.1.3 -s 172.18.0.0/16 -I -H -o -37
>                 |          responses            |     TX timestamp offset (ns)
> rate   clients |  lost invalid   basic  xleave |    min    mean     max stddev
> 1000       100   0.00%   0.00%   0.00% 100.00%      -44      +0     +61     19
> 1500       150   0.00%   0.00%   0.00% 100.00%       -6     +39     +81     16
> 2250       225   0.00%   0.00%   0.00% 100.00%      -22     +25     +69     15
> 3375       337   0.00%   0.00%   0.00% 100.00%      -28     +15     +56     14
> 5062       506   0.00%   0.00%   0.00% 100.00%       +7     +78    +143     27
> 7593       759   0.00%   0.00%   0.00% 100.00%      -54     +24    +144     47
> 11389     1138   0.00%   0.00%   0.00% 100.00%      -90     -33     +28     21
> 17083     1708   0.00%   0.00%   0.00% 100.00%      -50      -2     +35     14
> 25624     2562   0.00%   0.00%   0.00% 100.00%      -62      +7     +66     23
> 38436     3843   0.00%   0.00%   0.00% 100.00%      -33     +30   +5395     36
> 57654     5765   0.00%   0.00% 100.00%   0.00%
> 86481     8648   0.00%   0.00% 100.00%   0.00%
> 129721   12972   0.00%   0.00% 100.00%   0.00%
> 194581   16384  19.50%   0.00%  80.50%   0.00%
> 291871   16384  35.81%   0.00%  64.19%   0.00%
> 437806   16384  55.40%   0.00%  44.60%   0.00%
> 
> [1] https://github.com/mlichvar/ntpperf
> 
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
>   drivers/net/ethernet/intel/igc/igc.h      |  2 +-
>   drivers/net/ethernet/intel/igc/igc_main.c |  2 +-
>   drivers/net/ethernet/intel/igc/igc_ptp.c  | 15 +++++----------
>   3 files changed, 7 insertions(+), 12 deletions(-)

Tested-by: Naama Meir <naamax.meir@linux.intel.com>
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  reply	other threads:[~2023-06-20 19:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-07 21:32 [Intel-wired-lan] [PATCH iwl-net v4 0/4] igc: TX timestamping fixes Vinicius Costa Gomes
2023-06-07 21:32 ` [Intel-wired-lan] [PATCH iwl-net v4 1/4] igc: Fix race condition in PTP tx code Vinicius Costa Gomes
2023-06-19  7:29   ` naamax.meir
2023-06-07 21:32 ` [Intel-wired-lan] [PATCH iwl-net v4 2/4] igc: Check if hardware TX timestamping is enabled earlier Vinicius Costa Gomes
2023-06-20  6:54   ` naamax.meir
2023-06-07 21:32 ` [Intel-wired-lan] [PATCH iwl-net v4 3/4] igc: Retrieve TX timestamp during interrupt handling Vinicius Costa Gomes
2023-06-20 19:02   ` naamax.meir [this message]
2023-06-07 21:32 ` [Intel-wired-lan] [PATCH iwl-net v4 4/4] igc: Work around HW bug causing missing timestamps Vinicius Costa Gomes
2023-06-22  8:59   ` naamax.meir

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