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Subject: Re: [PATCH net v4 1/2] net: sched: fix packet stuck problem for
 lockless qdisc
From:   Yunsheng Lin <linyunsheng@huawei.com>
To:     Michal Kubecek <mkubecek@suse.cz>
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Date:   Fri, 23 Apr 2021 17:42:08 +0800
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On 2021/4/21 17:25, Yunsheng Lin wrote:
> On 2021/4/21 16:44, Michal Kubecek wrote:
> 
>>
>> I'll try running some tests also on other architectures, including arm64
>> and s390x (to catch potential endinanity issues).

I tried debugging nperf in arm64, with the below patch:
diff --git a/client/main.c b/client/main.c
index 429634d..de1a3ef 100644
--- a/client/main.c
+++ b/client/main.c
@@ -63,7 +63,10 @@ static int client_init(void)
        ret = client_set_usr1_handler();
        if (ret < 0)
                return ret;
-       return ignore_signal(SIGPIPE);
+       //return ignore_signal(SIGPIPE);
+       signal(SIGPIPE, SIG_IGN);
+
+       return 0;
 }

 static int ctrl_send_start(struct client_config *config)
diff --git a/client/worker.c b/client/worker.c
index ac026893..d269311 100644
--- a/client/worker.c
+++ b/client/worker.c
@@ -7,7 +7,7 @@
 #include "worker.h"
 #include "main.h"

-#define WORKER_STACK_SIZE 16384
+#define WORKER_STACK_SIZE 131072

 struct client_worker_data *workers_data;
 union sockaddr_any test_addr;

It has below error output:

../nperf/nperf -H 127.0.0.1 -l 3 -i 1 --exact -t TCP_STREAM -M 1
server: 127.0.0.1, port 12543
iterations: 1, threads: 1, test length: 3
test: TCP_STREAM, message size: 1048576

run test begin
send begin
send done: -32
failed to receive server stats
*** Iteration 1 failed, quitting. ***


Tcpdump has below output:
09:55:12.253341 IP localhost.53080 > localhost.12543: Flags [S], seq 3954442980, win 65495, options [mss 65495,sackOK,TS val 3268837738 ecr 0,nop,wscale 7], length 0
09:55:12.253363 IP localhost.12543 > localhost.53080: Flags [S.], seq 4240541653, ack 3954442981, win 65483, options [mss 65495,sackOK,TS val 3268837738 ecr 3268837738,nop,wscale 7], length 0
09:55:12.253379 IP localhost.53080 > localhost.12543: Flags [.], ack 1, win 512, options [nop,nop,TS val 3268837738 ecr 3268837738], length 0
09:55:12.253412 IP localhost.53080 > localhost.12543: Flags [P.], seq 1:29, ack 1, win 512, options [nop,nop,TS val 3268837738 ecr 3268837738], length 28
09:55:12.253863 IP localhost.12543 > localhost.53080: Flags [P.], seq 1:17, ack 29, win 512, options [nop,nop,TS val 3268837739 ecr 3268837738], length 16
09:55:12.253891 IP localhost.53080 > localhost.12543: Flags [.], ack 17, win 512, options [nop,nop,TS val 3268837739 ecr 3268837739], length 0
09:55:12.254265 IP localhost.12543 > localhost.53080: Flags [F.], seq 17, ack 29, win 512, options [nop,nop,TS val 3268837739 ecr 3268837739], length 0
09:55:12.301992 IP localhost.53080 > localhost.12543: Flags [.], ack 18, win 512, options [nop,nop,TS val 3268837787 ecr 3268837739], length 0
09:55:15.254389 IP localhost.53080 > localhost.12543: Flags [F.], seq 29, ack 18, win 512, options [nop,nop,TS val 3268840739 ecr 3268837739], length 0
09:55:15.254426 IP localhost.12543 > localhost.53080: Flags [.], ack 30, win 512, options [nop,nop,TS val 3268840739 ecr 3268840739], length 0


Any idea what went wrong here?

Also, Would you mind running netperf to see if there is similar issue
in your system?

>>
>> Michal
>>
>> .
>>
> 
> 
> .
>