| #!/usr/bin/env python |
| # @lint-avoid-python-3-compatibility-imports |
| # |
| # virtiostat Show virtio devices input/output statistics. |
| # For Linux, uses BCC, eBPF. |
| # |
| # USAGE: virtiostat [-h] [-T] [-D] [-d DRIVER] [-n DEVNAME] [INTERVAL] [COUNT] |
| # |
| # Copyright (c) 2021 zhenwei pi |
| # Licensed under the Apache License, Version 2.0 (the "License") |
| # |
| # 13-Feb-2021 zhenwei pi Created this. |
| |
| from __future__ import print_function |
| from bcc import BPF |
| from time import sleep, strftime |
| import argparse |
| |
| # arguments |
| examples = """examples: |
| ./virtiostat # print 3(default) second summaries |
| ./virtiostat 1 10 # print 1 second summaries, 10 times |
| ./virtiostat -T # show timestamps |
| ./virtiostat -d virtio_blk # only show virtio block devices |
| ./virtiostat -n virtio0 # only show virtio0 device |
| ./virtiostat -D # show debug bpf text |
| """ |
| parser = argparse.ArgumentParser( |
| description="Show virtio devices input/output statistics", |
| formatter_class=argparse.RawDescriptionHelpFormatter, |
| epilog=examples) |
| parser.add_argument("interval", nargs="?", default=3, |
| help="output interval, in seconds") |
| parser.add_argument("count", nargs="?", default=99999999, |
| help="number of outputs") |
| parser.add_argument("-T", "--timestamp", action="store_true", |
| help="show timestamp on output") |
| parser.add_argument("-d", "--driver", |
| help="filter for driver name") |
| parser.add_argument("-n", "--devname", |
| help="filter for device name") |
| parser.add_argument("-D", "--debug", action="store_true", |
| help="print BPF program before starting (for debugging purposes)") |
| parser.add_argument("--ebpf", action="store_true", |
| help=argparse.SUPPRESS) |
| args = parser.parse_args() |
| |
| # define BPF program |
| bpf_text = """ |
| #include <linux/virtio.h> |
| #include <bcc/proto.h> |
| |
| /* typically virtio scsi has max SGs of 6 */ |
| #define VIRTIO_MAX_SGS 6 |
| /* typically virtio blk has max SEG of 128 */ |
| #define SG_MAX 128 |
| |
| /* local strcmp function, max length 16 to protect instruction loops */ |
| #define CMPMAX 16 |
| |
| static int local_strcmp(const char *cs, const char *ct) |
| { |
| int len = 0; |
| unsigned char c1, c2; |
| |
| while (len++ < CMPMAX) { |
| c1 = *cs++; |
| c2 = *ct++; |
| if (c1 != c2) |
| return c1 < c2 ? -1 : 1; |
| if (!c1) |
| break; |
| } |
| return 0; |
| } |
| |
| typedef struct virtio_stat { |
| char driver[16]; |
| char dev[12]; |
| char vqname[12]; |
| u32 in_sgs; |
| u32 out_sgs; |
| u64 in_bw; |
| u64 out_bw; |
| } virtio_stat_t; |
| |
| BPF_HASH(stats, u64, virtio_stat_t); |
| |
| static struct scatterlist *__sg_next(struct scatterlist *sgp) |
| { |
| struct scatterlist sg; |
| |
| bpf_probe_read_kernel(&sg, sizeof(sg), sgp); |
| if (sg_is_last(&sg)) |
| return NULL; |
| |
| sgp++; |
| |
| bpf_probe_read_kernel(&sg, sizeof(sg), sgp); |
| if (unlikely(sg_is_chain(&sg))) |
| sgp = sg_chain_ptr(&sg); |
| |
| return sgp; |
| } |
| |
| static u64 count_len(struct scatterlist **sgs, unsigned int num) |
| { |
| u64 length = 0; |
| unsigned int i, n; |
| struct scatterlist *sgp = NULL; |
| |
| for (i = 0; (i < VIRTIO_MAX_SGS) && (i < num); i++) { |
| for (n = 0, sgp = sgs[i]; sgp && (n < SG_MAX); sgp = __sg_next(sgp)) { |
| length += sgp->length; |
| n++; |
| } |
| |
| /* Suggested by Yonghong Song: |
| * IndVarSimplifyPass with clang 12 may cause verifier failure: |
| * ; for (i = 0; (i < VIRTIO_MAX_SGS) && (i < num); i++) { // Line 60 |
| * 90: 15 08 15 00 00 00 00 00 if r8 == 0 goto +21 |
| * 91: bf 81 00 00 00 00 00 00 r1 = r8 |
| * 92: 07 01 00 00 ff ff ff ff r1 += -1 |
| * 93: 67 01 00 00 20 00 00 00 r1 <<= 32 |
| * 94: 77 01 00 00 20 00 00 00 r1 >>= 32 |
| * 95: b7 02 00 00 05 00 00 00 r2 = 5 |
| * 96: 2d 12 01 00 00 00 00 00 if r2 > r1 goto +1 |
| * 97: b7 08 00 00 06 00 00 00 r8 = 6 |
| * 98: b7 02 00 00 00 00 00 00 r2 = 0 |
| * 99: b7 09 00 00 00 00 00 00 r9 = 0 |
| * 100: 7b 8a 68 ff 00 00 00 00 *(u64 *)(r10 - 152) = r8 |
| * 101: 05 00 35 00 00 00 00 00 goto +53 |
| * Note that r1 is refined by r8 is saved to stack for later use. |
| * This will give verifier u64_max loop bound and eventually cause |
| * verification failure. Workaround with the below asm code. |
| */ |
| #if __clang_major__ >= 7 |
| asm volatile("" : "=r"(i) : "0"(i)); |
| #endif |
| } |
| |
| return length; |
| } |
| |
| static void record(struct virtqueue *vq, struct scatterlist **sgs, |
| unsigned int out_sgs, unsigned int in_sgs) |
| { |
| virtio_stat_t newvs = {0}; |
| virtio_stat_t *vs; |
| u64 key = (u64)vq; |
| u64 in_bw = 0; |
| |
| DRIVERFILTER |
| DEVNAMEFILTER |
| |
| /* Workaround: separate two count_len() calls, one here and the |
| * other below. Otherwise, compiler may generate some spills which |
| * harms verifier pruning. This happens in llvm12, but not llvm4. |
| * Below code works on both cases. |
| */ |
| if (in_sgs) |
| in_bw = count_len(sgs + out_sgs, in_sgs); |
| |
| vs = stats.lookup(&key); |
| if (!vs) { |
| bpf_probe_read_kernel_str(newvs.driver, sizeof(newvs.driver), vq->vdev->dev.driver->name); |
| bpf_probe_read_kernel_str(newvs.dev, sizeof(newvs.dev), vq->vdev->dev.kobj.name); |
| bpf_probe_read_kernel_str(newvs.vqname, sizeof(newvs.vqname), vq->name); |
| newvs.out_sgs = out_sgs; |
| newvs.in_sgs = in_sgs; |
| if (out_sgs) |
| newvs.out_bw = count_len(sgs, out_sgs); |
| newvs.in_bw = in_bw; |
| stats.update(&key, &newvs); |
| } else { |
| vs->out_sgs += out_sgs; |
| vs->in_sgs += in_sgs; |
| if (out_sgs) |
| vs->out_bw += count_len(sgs, out_sgs); |
| vs->in_bw += in_bw; |
| } |
| } |
| |
| int trace_virtqueue_add_sgs(struct pt_regs *ctx, struct virtqueue *vq, |
| struct scatterlist **sgs, unsigned int out_sgs, |
| unsigned int in_sgs, void *data, gfp_t gfp) |
| |
| { |
| record(vq, sgs, out_sgs, in_sgs); |
| |
| return 0; |
| } |
| |
| int trace_virtqueue_add_outbuf(struct pt_regs *ctx, struct virtqueue *vq, |
| struct scatterlist *sg, unsigned int num, |
| void *data, gfp_t gfp) |
| { |
| record(vq, &sg, 1, 0); |
| |
| return 0; |
| } |
| |
| int trace_virtqueue_add_inbuf(struct pt_regs *ctx, struct virtqueue *vq, |
| struct scatterlist *sg, unsigned int num, |
| void *data, gfp_t gfp) |
| { |
| record(vq, &sg, 0, 1); |
| |
| return 0; |
| } |
| |
| int trace_virtqueue_add_inbuf_ctx(struct pt_regs *ctx, struct virtqueue *vq, |
| struct scatterlist *sg, unsigned int num, |
| void *data, void *_ctx, gfp_t gfp) |
| { |
| record(vq, &sg, 0, 1); |
| |
| return 0; |
| } |
| """ |
| |
| # filter for driver name |
| if args.driver: |
| bpf_text = bpf_text.replace('DRIVERFILTER', |
| """char filter_driver[] = \"%s\"; |
| char driver[16]; |
| bpf_probe_read_kernel_str(driver, sizeof(driver), vq->vdev->dev.driver->name); |
| if (local_strcmp(filter_driver, driver)) |
| return;""" % (args.driver)) |
| else: |
| bpf_text = bpf_text.replace('DRIVERFILTER', '') |
| |
| # filter for dev name |
| if args.devname: |
| bpf_text = bpf_text.replace('DEVNAMEFILTER', |
| """char filter_devname[] = \"%s\"; |
| char devname[16]; |
| bpf_probe_read_kernel_str(devname, sizeof(devname), vq->vdev->dev.kobj.name); |
| if (local_strcmp(filter_devname, devname)) |
| return;""" % (args.devname)) |
| else: |
| bpf_text = bpf_text.replace('DEVNAMEFILTER', '') |
| |
| |
| # debug mode: print bpf text |
| if args.debug: |
| print(bpf_text) |
| |
| # dump mode: print bpf text and exit |
| if args.ebpf: |
| print(bpf_text) |
| exit() |
| |
| # load BPF program |
| b = BPF(text=bpf_text) |
| b.attach_kprobe(event="virtqueue_add_sgs", fn_name="trace_virtqueue_add_sgs") |
| b.attach_kprobe(event="virtqueue_add_outbuf", fn_name="trace_virtqueue_add_outbuf") |
| b.attach_kprobe(event="virtqueue_add_inbuf", fn_name="trace_virtqueue_add_inbuf") |
| b.attach_kprobe(event="virtqueue_add_inbuf_ctx", fn_name="trace_virtqueue_add_inbuf_ctx") |
| |
| print("Tracing virtio devices statistics ... Hit Ctrl-C to end.") |
| |
| # start main loop |
| exiting = 0 if args.interval else 1 |
| seconds = 0 |
| while (1): |
| try: |
| sleep(int(args.interval)) |
| seconds = seconds + int(args.interval) |
| except KeyboardInterrupt: |
| exiting = 1 |
| |
| if args.timestamp: |
| print("%-8s\n" % strftime("%H:%M:%S"), end="") |
| else: |
| print("--------", end="\n") |
| |
| print("%14s %8s %10s %7s %7s %14s %14s" % ("Driver", "Device", "VQ Name", "In SGs", "Out SGs", "In BW", "Out BW")) |
| stats = b.get_table("stats") |
| for k, v in sorted(stats.items(), key=lambda vs: vs[1].dev): |
| print("%14s %8s %10s %7d %7d %14d %14d" % (v.driver, v.dev, v.vqname, v.in_sgs, v.out_sgs, v.in_bw, v.out_bw)) |
| |
| stats.clear() |
| |
| if exiting or seconds >= int(args.count): |
| exit() |
