Re: [Qemu-devel] [PATCH 1/6] tests: Add basic migration precopy test

[Dr. David Alan Gilbert]

* Daniel P. Berrange (address@hidden) wrote:
> On Wed, Oct 04, 2017 at 12:39:28PM +0200, Juan Quintela wrote:
> > Signed-off-by: Juan Quintela <address@hidden>
> > ---
> >  tests/Makefile.include |   3 +
> >  tests/migration-test.c | 497 
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 500 insertions(+)
> >  create mode 100644 tests/migration-test.c
> > 
> 
> 
> > +
> > +/* A simple PC boot sector that modifies memory (1-100MB) quickly
> > + * outputing a 'B' every so often if it's still running.
> > + */
> 
> 
> Can you add a comment about what it is actually doing to dirty the memory.

Yes, so this is the code from the postcopy tests, the commit message
ea0c6d62 has the actual source for it.

> eg is it writing a different random value at each byte of RAM, or picking
> a random value at the stasrt of each iteration and writing it to all RAM,
> or it is just xoring current memory contents, or something else ?
> 
> Understanding this would be helpful in understanding how well the tests
> for xbzrle / compression are working, because the pattern of dirtying
> memory will affect whether the compression does anything useful or not.

It rolls through 100MB of RAM, incrementing the 1st byte of each page in
sequence and then goes back and does it again.  So it should be
excellent for xbzrle.

Dave

> > +unsigned char bootsect[] = {
> > +  0xfa, 0x0f, 0x01, 0x16, 0x74, 0x7c, 0x66, 0xb8, 0x01, 0x00, 0x00, 0x00,
> > +  0x0f, 0x22, 0xc0, 0x66, 0xea, 0x20, 0x7c, 0x00, 0x00, 0x08, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe4, 0x92, 0x0c, 0x02,
> > +  0xe6, 0x92, 0xb8, 0x10, 0x00, 0x00, 0x00, 0x8e, 0xd8, 0x66, 0xb8, 0x41,
> > +  0x00, 0x66, 0xba, 0xf8, 0x03, 0xee, 0xb3, 0x00, 0xb8, 0x00, 0x00, 0x10,
> > +  0x00, 0xfe, 0x00, 0x05, 0x00, 0x10, 0x00, 0x00, 0x3d, 0x00, 0x00, 0x40,
> > +  0x06, 0x7c, 0xf2, 0xfe, 0xc3, 0x75, 0xe9, 0x66, 0xb8, 0x42, 0x00, 0x66,
> > +  0xba, 0xf8, 0x03, 0xee, 0xeb, 0xde, 0x66, 0x90, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00,
> > +  0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00, 0x27, 0x00, 0x5c, 0x7c,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> > +  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa
> > +};
> > +
> > +static void init_bootfile_x86(const char *bootpath)
> > +{
> > +    FILE *bootfile = fopen(bootpath, "wb");
> > +
> > +    g_assert_cmpint(fwrite(bootsect, 512, 1, bootfile), ==, 1);
> > +    fclose(bootfile);
> > +}
> > +
> > +static void init_bootfile_ppc(const char *bootpath)
> > +{
> > +    FILE *bootfile;
> > +    char buf[MIN_NVRAM_SIZE];
> > +    ChrpNvramPartHdr *header = (ChrpNvramPartHdr *)buf;
> > +
> > +    memset(buf, 0, MIN_NVRAM_SIZE);
> > +
> > +    /* Create a "common" partition in nvram to store boot-command property 
> > */
> > +
> > +    header->signature = CHRP_NVPART_SYSTEM;
> > +    memcpy(header->name, "common", 6);
> > +    chrp_nvram_finish_partition(header, MIN_NVRAM_SIZE);
> > +
> > +    /* FW_MAX_SIZE is 4MB, but slof.bin is only 900KB,
> > +     * so let's modify memory between 1MB and 100MB
> > +     * to do like PC bootsector
> > +     */
> > +
> > +    sprintf(buf + 16,
> > +            "boot-command=hex .\" _\" begin %x %x do i c@ 1 + i c! 1000 
> > +loop "
> > +            ".\" B\" 0 until", end_address, start_address);
> > +
> > +    /* Write partition to the NVRAM file */
> > +
> > +    bootfile = fopen(bootpath, "wb");
> > +    g_assert_cmpint(fwrite(buf, MIN_NVRAM_SIZE, 1, bootfile), ==, 1);
> > +    fclose(bootfile);
> > +}
> > +
> > +/*
> > + * Wait for some output in the serial output file,
> > + * we get an 'A' followed by an endless string of 'B's
> > + * but on the destination we won't have the A.
> > + */
> > +static void wait_for_serial(const char *side)
> > +{
> > +    char *serialpath = g_strdup_printf("%s/%s", tmpfs, side);
> > +    FILE *serialfile = fopen(serialpath, "r");
> > +    const char *arch = qtest_get_arch();
> > +    int started = (strcmp(side, "src_serial") == 0 &&
> > +                   strcmp(arch, "ppc64") == 0) ? 0 : 1;
> > +
> > +    g_free(serialpath);
> > +    do {
> > +        int readvalue = fgetc(serialfile);
> > +
> > +        if (!started) {
> > +            /* SLOF prints its banner before starting test,
> > +             * to ignore it, mark the start of the test with '_',
> > +             * ignore all characters until this marker
> > +             */
> > +            switch (readvalue) {
> > +            case '_':
> > +                started = 1;
> > +                break;
> > +            case EOF:
> > +                fseek(serialfile, 0, SEEK_SET);
> > +                usleep(1000);
> > +                break;
> > +            }
> > +            continue;
> > +        }
> > +        switch (readvalue) {
> > +        case 'A':
> > +            /* Fine */
> > +            break;
> > +
> > +        case 'B':
> > +            /* It's alive! */
> > +            fclose(serialfile);
> > +            return;
> > +
> > +        case EOF:
> > +            started = (strcmp(side, "src_serial") == 0 &&
> > +                       strcmp(arch, "ppc64") == 0) ? 0 : 1;
> > +            fseek(serialfile, 0, SEEK_SET);
> > +            usleep(1000);
> > +            break;
> > +
> > +        default:
> > +            fprintf(stderr, "Unexpected %d on %s serial\n", readvalue, 
> > side);
> > +            g_assert_not_reached();
> > +        }
> > +    } while (true);
> > +}
> > +
> > +/*
> > + * Events can get in the way of responses we are actually waiting for.
> > + */
> > +static QDict *return_or_event(QDict *response, QTestState *who)
> > +{
> > +    const char *event_string;
> > +    if (!qdict_haskey(response, "event")) {
> > +        return response;
> > +    }
> > +
> > +    /* OK, it was an event */
> > +    event_string = qdict_get_str(response, "event");
> > +    if (!strcmp(event_string, "STOP")) {
> > +        got_stop = true;
> > +    }
> > +    QDECREF(response);
> > +    return return_or_event(qtest_qmp_receive(who), who);
> > +}
> > +
> > +
> > +/*
> > + * It's tricky to use qemu's migration event capability with qtest,
> > + * events suddenly appearing confuse the qmp()/hmp() responses.
> > + * so wait for a couple of passes to have happened before
> > + * going postcopy.
> > + */
> > +
> > +static uint64_t get_migration_pass(QTestState *who)
> > +{
> > +    QDict *rsp, *rsp_return, *rsp_ram;
> > +    uint64_t result;
> > +
> > +    rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"), who);
> > +    rsp_return = qdict_get_qdict(rsp, "return");
> > +    if (!qdict_haskey(rsp_return, "ram")) {
> > +        /* Still in setup */
> > +        result = 0;
> > +    } else {
> > +        rsp_ram = qdict_get_qdict(rsp_return, "ram");
> > +        result = qdict_get_try_int(rsp_ram, "dirty-sync-count", 0);
> > +    }
> > +    QDECREF(rsp);
> > +    return result;
> > +}
> > +
> > +static void wait_for_migration_complete(QTestState *who)
> > +{
> > +    bool completed;
> > +
> > +    do {
> > +        QDict *rsp, *rsp_return;
> > +        const char *status;
> > +
> > +        rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"), who);
> > +        rsp_return = qdict_get_qdict(rsp, "return");
> > +        status = qdict_get_str(rsp_return, "status");
> > +        completed = strcmp(status, "completed") == 0;
> > +        g_assert_cmpstr(status, !=,  "failed");
> > +        QDECREF(rsp);
> > +        usleep(1000 * 100);
> > +    } while (!completed);
> > +}
> > +
> > +static void wait_for_migration_pass(QTestState *who)
> > +{
> > +    uint64_t initial_pass = get_migration_pass(who);
> > +    uint64_t pass;
> > +
> > +    /* Wait for the 1st sync */
> > +    do {
> > +        initial_pass = get_migration_pass(who);
> > +        if (got_stop || initial_pass) {
> > +            break;
> > +        }
> > +        usleep(1000 * 100);
> > +    } while (true);
> > +
> > +    do {
> > +        usleep(1000 * 100);
> > +        pass = get_migration_pass(who);
> > +    } while (pass == initial_pass && !got_stop);
> > +}
> > +
> > +static void check_guests_ram(QTestState *who)
> > +{
> > +    /* Our ASM test will have been incrementing one byte from each page 
> > from
> > +     * 1MB to <100MB in order.
> > +     * This gives us a constraint that any page's byte should be equal or 
> > less
> > +     * than the previous pages byte (mod 256); and they should all be equal
> > +     * except for one transition at the point where we meet the 
> > incrementer.
> > +     * (We're running this with the guest stopped).
> > +     */
> > +    unsigned address;
> > +    uint8_t first_byte;
> > +    uint8_t last_byte;
> > +    bool hit_edge = false;
> > +    bool bad = false;
> > +
> > +    qtest_memread(who, start_address, &first_byte, 1);
> > +    last_byte = first_byte;
> > +
> > +    for (address = start_address + 4096; address < end_address; address += 
> > 4096)
> > +    {
> > +        uint8_t b;
> > +        qtest_memread(who, address, &b, 1);
> > +        if (b != last_byte) {
> > +            if (((b + 1) % 256) == last_byte && !hit_edge) {
> > +                /* This is OK, the guest stopped at the point of
> > +                 * incrementing the previous page but didn't get
> > +                 * to us yet.
> > +                 */
> > +                hit_edge = true;
> > +            } else {
> > +                fprintf(stderr, "Memory content inconsistency at %x"
> > +                                " first_byte = %x last_byte = %x current = 
> > %x"
> > +                                " hit_edge = %x\n",
> > +                                address, first_byte, last_byte, b, 
> > hit_edge);
> > +                bad = true;
> > +            }
> > +        }
> > +        last_byte = b;
> > +    }
> > +    g_assert_false(bad);
> > +}
> > +
> > +static void cleanup(const char *filename)
> > +{
> > +    char *path = g_strdup_printf("%s/%s", tmpfs, filename);
> > +
> > +    unlink(path);
> > +    g_free(path);
> > +}
> > +
> > +static void test_migrate_start(QTestState **from, QTestState **to,
> > +                               const char *uri)
> > +{
> > +    gchar *cmd_src, *cmd_dst;
> > +    char *bootpath = g_strdup_printf("%s/bootsect", tmpfs);
> > +    const char *arch = qtest_get_arch();
> > +
> > +    got_stop = false;
> > +
> > +    if (strcmp(arch, "i386") == 0 || strcmp(arch, "x86_64") == 0) {
> > +        init_bootfile_x86(bootpath);
> > +        cmd_src = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
> > +                                  " -name pcsource,debug-threads=on"
> > +                                  " -serial file:%s/src_serial"
> > +                                  " -drive file=%s,format=raw",
> > +                                  tmpfs, bootpath);
> > +        cmd_dst = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
> > +                                  " -name pcdest,debug-threads=on"
> > +                                  " -serial file:%s/dest_serial"
> > +                                  " -drive file=%s,format=raw"
> > +                                  " -incoming %s",
> > +                                  tmpfs, bootpath, uri);
> > +    } else if (strcmp(arch, "ppc64") == 0) {
> > +        const char *accel;
> > +
> > +        /* On ppc64, the test only works with kvm-hv, but not with kvm-pr 
> > */
> > +        accel = access("/sys/module/kvm_hv", F_OK) ? "tcg" : "kvm:tcg";
> > +        init_bootfile_ppc(bootpath);
> > +        cmd_src = g_strdup_printf("-machine accel=%s -m 256M"
> > +                                  " -name pcsource,debug-threads=on"
> > +                                  " -serial file:%s/src_serial"
> > +                                  " -drive file=%s,if=pflash,format=raw",
> > +                                  accel, tmpfs, bootpath);
> > +        cmd_dst = g_strdup_printf("-machine accel=%s -m 256M"
> > +                                  " -name pcdest,debug-threads=on"
> > +                                  " -serial file:%s/dest_serial"
> > +                                  " -incoming %s",
> > +                                  accel, tmpfs, uri);
> > +    } else {
> > +        g_assert_not_reached();
> > +    }
> > +
> > +    g_free(bootpath);
> > +
> > +    *from = qtest_start(cmd_src);
> > +    g_free(cmd_src);
> > +
> > +    *to = qtest_init(cmd_dst);
> > +    g_free(cmd_dst);
> > +}
> > +
> > +static void test_migrate_end(QTestState *from, QTestState *to)
> > +{
> > +    unsigned char dest_byte_a, dest_byte_b, dest_byte_c, dest_byte_d;
> > +
> > +    qtest_quit(from);
> > +
> > +    qtest_memread(to, start_address, &dest_byte_a, 1);
> > +
> > +    /* Destination still running, wait for a byte to change */
> > +    do {
> > +        qtest_memread(to, start_address, &dest_byte_b, 1);
> > +        usleep(10 * 1000);
> > +    } while (dest_byte_a == dest_byte_b);
> > +
> > +    qtest_qmp_discard_response(to, "{ 'execute' : 'stop'}");
> > +    /* With it stopped, check nothing changes */
> > +    qtest_memread(to, start_address, &dest_byte_c, 1);
> > +    sleep(1);
> > +    qtest_memread(to, start_address, &dest_byte_d, 1);
> > +    g_assert_cmpint(dest_byte_c, ==, dest_byte_d);
> > +
> > +    check_guests_ram(to);
> > +
> > +    qtest_quit(to);
> > +
> > +    cleanup("bootsect");
> > +    cleanup("migsocket");
> > +    cleanup("src_serial");
> > +    cleanup("dest_serial");
> > +}
> > +
> > +static void migrate(QTestState *who, const char *uri)
> > +{
> > +    QDict *rsp;
> > +    gchar *cmd;
> > +
> > +    cmd = g_strdup_printf("{ 'execute': 'migrate',"
> > +                          "'arguments': { 'uri': '%s' } }",
> > +                          uri);
> > +    rsp = qtest_qmp(who, cmd);
> > +    g_free(cmd);
> > +    g_assert(qdict_haskey(rsp, "return"));
> > +    QDECREF(rsp);
> > +}
> > +
> > +static void migrate_set_parameter(QTestState *who, const char *parameter,
> > +                                  const char *value)
> > +{
> > +    QDict *rsp;
> > +    gchar *cmd;
> > +
> > +    cmd = g_strdup_printf("{ 'execute': 'migrate-set-parameters',"
> > +                          "'arguments': { '%s': %s } }",
> > +                          parameter, value);
> > +    rsp = qtest_qmp(who, cmd);
> > +    g_free(cmd);
> > +    g_assert(qdict_haskey(rsp, "return"));
> > +    QDECREF(rsp);
> > +}
> > +
> > +static void test_precopy(const char *uri)
> > +{
> > +    QTestState *from, *to;
> > +
> > +    test_migrate_start(&from, &to, uri);
> > +
> > +    /* We want to pick a speed slow enough that the test completes
> > +     * quickly, but that it doesn't complete precopy even on a slow
> > +     * machine, so also set the downtime.
> > +     */
> > +    /* 100 ms */
> > +    migrate_set_parameter(from, "downtime-limit", "100");
> > +    /* 1MB/s slow*/
> > +    migrate_set_parameter(from, "max-bandwidth", "100000000");
> > +
> > +    /* Wait for the first serial output from the source */
> > +    wait_for_serial("src_serial");
> > +
> > +    migrate(from, uri);
> > +
> > +    wait_for_migration_pass(from);
> > +
> > +    /* 1GB/s now it should converge */
> > +    migrate_set_parameter(from, "max-bandwidth", "1000000000");
> > +
> > +    if (!got_stop) {
> > +        qtest_qmp_eventwait(from, "STOP");
> > +    }
> > +    qtest_qmp_eventwait(to, "RESUME");
> > +
> > +    wait_for_serial("dest_serial");
> > +    wait_for_migration_complete(from);
> > +
> > +    test_migrate_end(from, to);
> > +}
> > +
> > +static void test_precopy_unix(void)
> > +{
> > +    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> > +
> > +    test_precopy(uri);
> > +    g_free(uri);
> > +}
> > +
> > +int main(int argc, char **argv)
> > +{
> > +    char template[] = "/tmp/migration-test-XXXXXX";
> > +    int ret;
> > +
> > +    g_test_init(&argc, &argv, NULL);
> > +
> > +    tmpfs = mkdtemp(template);
> > +    if (!tmpfs) {
> > +        g_test_message("mkdtemp on path (%s): %s\n", template, 
> > strerror(errno));
> > +    }
> > +    g_assert(tmpfs);
> > +
> > +    module_call_init(MODULE_INIT_QOM);
> > +
> > +    qtest_add_func("/migration/precopy/unix", test_precopy_unix);
> > +
> > +    ret = g_test_run();
> > +
> > +    g_assert_cmpint(ret, ==, 0);
> > +
> > +    ret = rmdir(tmpfs);
> > +    if (ret != 0) {
> > +        g_test_message("unable to rmdir: path (%s): %s\n",
> > +                       tmpfs, strerror(errno));
> > +    }
> > +
> > +    return ret;
> > +}
> > -- 
> > 2.13.5
> > 
> > 
> 
> Regards,
> Daniel
> -- 
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> |: https://libvirt.org         -o-            https://fstop138.berrange.com :|
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--
Dr. David Alan Gilbert / address@hidden / Manchester, UK