mirror of
https://github.com/xdp-project/bpf-examples.git
synced 2024-05-06 15:54:53 +00:00
71d1479d1d
Digging into the return value of netdev_pick_tx(). Want to be able to debug the case where a socket selects another queue_id. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
43 lines
882 B
Plaintext
Executable File
43 lines
882 B
Plaintext
Executable File
#!/usr/bin/bpftrace
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//BEGIN {
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// printf("Monitor TXQ usage\n");
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// printf(" - Remember: BPF set queue_mapping is one-less here (zero-indexed)\n");
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//}
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tracepoint:net:net_dev_start_xmit {
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$qm = args->queue_mapping;
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$dev = str(args->name, 16);
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@stat_txq_usage[$dev] = lhist($qm, 0,32,1);
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}
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/*
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* More precisely we actually want to see what netdev_pick_tx() is
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* selecting, as sockets can possibly return another queue_id.
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*/
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kprobe:netdev_pick_tx {
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$dev = ((struct net_device *)arg0)->name;
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@record[cpu] = $dev;
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}
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kretprobe:netdev_pick_tx {
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$dev = @record[cpu];
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@netdev_pick_tx[$dev] = lhist(retval, 0,32,1);
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}
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/* Periodically print stats */
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interval:s:3
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{
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printf("\nPeriodic show stats - time: ");
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time();
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print(@stat_txq_usage);
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print(@netdev_pick_tx);
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}
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/* Default bpftrace will print all remaining maps at END */
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//END {
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// printf("END stats:\n");
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//}
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