[pve-devel] [PATCH 3/3] add downtime && expected_downtime query-migrate info

[Alexandre DERUMIER]

I'm looking into qemu src code,
in arch_init.c -> ram_save_iterate()

it should return false, to retry transfert iteration of remaining memory  , until the last step:ram_save_complete()

Seem that for Stefan, it's return 0 directly with migrate_set_downtime = 1.

I think interesting part is here:

Maybe can we add somes logs ? (BTW, is it possible to logs qemu STDOUT somewhere in a file ?)



    bwidth = qemu_get_clock_ns(rt_clock) - bwidth;
    bwidth = (bytes_transferred - bytes_transferred_last) / bwidth;

    /* if we haven't transferred anything this round, force
     * expected_downtime to a very high value, but without
     * crashing */
    if (bwidth == 0) {
        bwidth = 0.000001;
    }

    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

    expected_downtime = ram_save_remaining() * TARGET_PAGE_SIZE / bwidth;
    DPRINTF("ram_save_live: expected(%" PRIu64 ") <= max(" PRIu64 ")?\n",
            expected_downtime, migrate_max_downtime());

    if (expected_downtime <= migrate_max_downtime()) {             
        migration_bitmap_sync();
        expected_downtime = ram_save_remaining() * TARGET_PAGE_SIZE / bwidth;
        s->expected_downtime = expected_downtime / 1000000; /* ns -> ms */

        return expected_downtime <= migrate_max_downtime();
    }
    return 0;






----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag> 
Cc: "Alexandre DERUMIER" <aderumier at odiso.com>, pve-devel at pve.proxmox.com 
Envoyé: Vendredi 28 Décembre 2012 07:39:50 
Objet: RE: [pve-devel] [PATCH 3/3] add downtime && expected_downtime query-migrate info 

> >> Am 27.12.2012 16:21, schrieb Alexandre DERUMIER: 
> >>> But if it's work fine for you with 1s migrate_downtime, we need to 
> >>> find where the problem is in the current qemu 1.3 code ... (maybe 
> >>> qemu mailing can help) 
> >> To my last mails nobody answered... 
> > 
> > What information do you miss (what last mails?)? 
> Last mails to qemu mailing list. It was regarding my migration problems. 

Ah, yes. I will do further tests today to reproduce the bug here.