#!/usr/bin/python
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#
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# bitehist.py Block I/O size histogram.
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# For Linux, uses BCC, eBPF. See .c file.
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#
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# USAGE: bitesize
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#
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# Ctrl-C will print the partially gathered histogram then exit.
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#
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# Copyright (c) 2016 Allan McAleavy
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# Licensed under the Apache License, Version 2.0 (the "License")
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#
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# 05-Feb-2016 Allan McAleavy ran pep8 against file
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from bcc import BPF
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from time import sleep
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bpf_text = """
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#include <uapi/linux/ptrace.h>
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#include <linux/blkdev.h>
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struct proc_key_t {
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char name[TASK_COMM_LEN];
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u64 slot;
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};
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struct val_t {
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char name[TASK_COMM_LEN];
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};
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BPF_HISTOGRAM(dist, struct proc_key_t);
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BPF_HASH(commbyreq, struct request *, struct val_t);
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int trace_pid_start(struct pt_regs *ctx, struct request *req)
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{
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struct val_t val = {};
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if (bpf_get_current_comm(&val.name, sizeof(val.name)) == 0) {
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commbyreq.update(&req, &val);
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}
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return 0;
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}
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int do_count(struct pt_regs *ctx, struct request *req)
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{
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struct val_t *valp;
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valp = commbyreq.lookup(&req);
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if (valp == 0) {
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return 0;
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}
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if (req->__data_len > 0) {
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struct proc_key_t key = {.slot = bpf_log2l(req->__data_len / 1024)};
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bpf_probe_read(&key.name, sizeof(key.name),valp->name);
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dist.increment(key);
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}
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return 0;
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}
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"""
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# load BPF program
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b = BPF(text=bpf_text)
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b.attach_kprobe(event="blk_account_io_start", fn_name="trace_pid_start")
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b.attach_kprobe(event="blk_account_io_completion", fn_name="do_count")
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print("Tracing... Hit Ctrl-C to end.")
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# trace until Ctrl-C
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dist = b.get_table("dist")
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try:
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sleep(99999999)
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except KeyboardInterrupt:
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dist.print_log2_hist("Kbytes", "Process Name",
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section_print_fn=bytes.decode)
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