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Merged
alan-maguire merged 1 commit into from
Dec 19, 2024
Merged

netdev budget: fix criteria for budget increase #136

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netdev budget: fix criteria for budget increase 
because we can have net_rx_action() run on different processors
we may have cases where we do not see increases for every sample
but the increases do happen for different cpus; as such, relax
criteria for time_squeezed to simply increase from one sample to
the next.

Also fix budget test to verify budget + budget_usecs increase.

Signed-off-by: Alan Maguire <[email protected]>
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@alan-maguire
alan-maguire committed Dec 19, 2024
commit a9fa5ebcbfd9cd14a184387882291a0421f0edf3
5 changes: 1 addition & 4 deletions src/net_buffer_tuner.bpf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -120,10 +120,7 @@ int BPF_PROG(net_rx_action)
if (!last_time_squeezep)
return 0;
last_time_squeeze = *last_time_squeezep;
/* if time squeeze increased for every instance of
* net_rx_action() since last sample, we increase.
*/
if (time_squeeze <= (last_time_squeeze + bpftune_sample_rate))
if (time_squeeze <= last_time_squeeze)
return 0;
*last_time_squeezep = time_squeeze;
/* did not have previous time_squeeze value for comparison, bail. */
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15 changes: 12 additions & 3 deletions test/budget_test.sh
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Expand Up @@ -43,11 +43,14 @@ for FAMILY in ipv4 ipv6 ; do

test_start "$0|budget test to $ADDR:$PORT $FAMILY opts $CLIENT_OPTS $LATENCY"

budget_orig=($(sysctl -n net.core.netdev_max_backlog))
budget_orig=($(sysctl -n net.core.netdev_budget))
usecs_orig=($(sysctl -n net.core.netdev_budget_usecs))
test_setup true

sysctl -w net.core.netdev_budget=10
sysctl -w net.core.netdev_budget_usecs=100
budget_pre=($(sysctl -n net.core.netdev_budget))
usecs_pre=($(sysctl -n net.core.netdev_budget_usecs))
declare -A results
for MODE in baseline test ; do

Expand All @@ -60,7 +63,7 @@ for FAMILY in ipv4 ipv6 ; do
LOGSZ=$(wc -l $LOGFILE | awk '{print $1}')
LOGSZ=$(expr $LOGSZ + 1)
fi
test_run_cmd_local "ip netns exec $NETNS $IPERF3 -fm -t 20 $CLIENT_OPTS -c $PORT -c $ADDR" true
test_run_cmd_local "ip netns exec $NETNS $IPERF3 -fm -t 10 -P 20 $CLIENT_OPTS -c $PORT -c $ADDR" true
sleep $SLEEPTIME

sresults=$(grep -E "sender" ${CMDLOG} | awk '{print $7}')
Expand All @@ -80,10 +83,16 @@ for FAMILY in ipv4 ipv6 ; do
done

budget_post=($(sysctl -n net.core.netdev_budget))
usecs_post=($(sysctl -n net.core.netdev_budget_usecs))
sleep $SLEEPTIME
sysctl -w net.core.netdev_budget="$budget_orig"
sysctl -w net.core.netdev_budget_usecs="$usecs_orig"
echo "budget ${budget_pre} -> ${budget_post}"
echo "usecs ${usecs_pre} -> ${usecs_post}"
if [[ "$budget_post" -gt "$budget_pre" ]]; then
test_pass
if [[ "$usecs_post" -gt "$usecs_pre" ]]; then
test_pass
fi
fi
test_cleanup
done
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