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From: Juan Quintela <quintela@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: aarcange@redhat.com, yamahata@private.email.ne.jp,
	liang.z.li@intel.com, qemu-devel@nongnu.org, luis@cs.umu.se,
	amit.shah@redhat.com, pbonzini@redhat.com,
	david@gibson.dropbear.id.au
Subject: Re: [Qemu-devel] [PATCH v7 07/42] ram_debug_dump_bitmap: Dump a migration bitmap as text
Date: Mon, 13 Jul 2015 12:15:34 +0200	[thread overview]
Message-ID: <871tgcmkhl.fsf@neno.neno> (raw)
In-Reply-To: <20150619170418.GH2147@work-vm> (David Alan Gilbert's message of "Fri, 19 Jun 2015 18:04:19 +0100")

"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> * Juan Quintela (quintela@redhat.com) wrote:
>> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
>> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>> >
>> > Useful for debugging the migration bitmap and other bitmaps
>> > of the same format (including the sentmap in postcopy).
>> >
>> > The bitmap is printed to stderr.
>> > Lines that are all the expected value are excluded so the output
>> > can be quite compact for many bitmaps.
>> >
>> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> > ---
>> >  include/migration/migration.h |  1 +
>> >  migration/ram.c               | 38 ++++++++++++++++++++++++++++++++++++++
>> >  2 files changed, 39 insertions(+)
>> >
>> > diff --git a/include/migration/migration.h b/include/migration/migration.h
>> > index 9387c8c..b3a7f75 100644
>> > --- a/include/migration/migration.h
>> > +++ b/include/migration/migration.h
>> > @@ -144,6 +144,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void);
>> >  double xbzrle_mig_cache_miss_rate(void);
>> >  
>> >  void ram_handle_compressed(void *host, uint8_t ch, uint64_t size);
>> > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected);
>> >  
>> >  /**
>> >   * @migrate_add_blocker - prevent migration from proceeding
>> > diff --git a/migration/ram.c b/migration/ram.c
>> > index 57368e1..efc215a 100644
>> > --- a/migration/ram.c
>> > +++ b/migration/ram.c
>> > @@ -1051,6 +1051,44 @@ static void reset_ram_globals(void)
>> >  
>> >  #define MAX_WAIT 50 /* ms, half buffered_file limit */
>> >  
>> > +/*
>> > + * 'expected' is the value you expect the bitmap mostly to be full
>> > + * of; it won't bother printing lines that are all this value.
>> > + * If 'todump' is null the migration bitmap is dumped.
>> > + */
>> > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected)
>> > +{
>> > +    int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
>> > +
>> > +    int64_t cur;
>> > +    int64_t linelen = 128;
>> > +    char linebuf[129];
>> > +
>> > +    if (!todump) {
>> > +        todump = migration_bitmap;
>> > +    }
>> 
>> Why?  Just alssert that todump!= NULL?
>
> 'migration_bitmap' is static to ram.c, so allowing NULL to get
> you a dump of the migration_bitmap means that if you call this
> dump routine from any error path you're debugging anywhere in qemu
> then you can dump the migration bitmap.  e.g. I was adding calls
> to this in migration.c and migration/postcopy-ram.c in error
> paths I was trying to debug.

ok.

>
>> > +    for (cur = 0; cur < ram_pages; cur += linelen) {
>> > +        int64_t curb;
>> > +        bool found = false;
>> > +        /*
>> > +         * Last line; catch the case where the line length
>> > +         * is longer than remaining ram
>> > +         */
>> > +        if (cur + linelen > ram_pages) {
>> > +            linelen = ram_pages - cur;
>> > +        }
>> > +        for (curb = 0; curb < linelen; curb++) {
>> > +            bool thisbit = test_bit(cur + curb, todump);
>> > +            linebuf[curb] = thisbit ? '1' : '.';
>> 
>> Put 1 and 0?  Why the dot?
>
> It's easier to see an occasional '1' in a big field of .'s.

ok.

>
>> > +            found = found || (thisbit != expected);
>> > +        }
>> > +        if (found) {
>> > +            linebuf[curb] = '\0';
>> > +            fprintf(stderr,  "0x%08" PRIx64 " : %s\n", cur, linebuf);
>> > +        }
>> > +    }
>> > +}
>> 
>> 
>> And once here, why are we doing it this way?  We have
>> 
>> find_first_bit(addr, nbits) and find_first_zero_bit(addr, nbits) and
>> friends?
>> 
>> Doiwg the walk by hand looks weird, no?
>
> Here's a compile-tested-only version using find_  - it's bigger, if you think
> it's better I can use this instead:
>
> void ram_debug_dump_bitmap(unsigned long *todump, bool expected)
> {
>     int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
>
>     int64_t cur;
>     int64_t linelen = 128;
>
>     if (!todump) {
>         todump = migration_bitmap;
>     }
>
>     for (cur = 0; cur < ram_pages; cur += linelen) {
>         int64_t curb;
>         unsigned long next_bit;
>
>         /*
>          * Last line; catch the case where the line length
>          * is longer than remaining ram
>          */
>         if (cur + linelen > ram_pages) {
>             linelen = ram_pages - cur;
>         }
>         if (expected) {
>             next_bit = find_next_bit(todump, cur + linelen, cur);
>         } else {
>             next_bit = find_next_zero_bit(todump, cur + linelen, cur);
>         }
>         if (next_bit >= (cur + linelen)) {
>             continue;
>         }
>
>         for (curb = 0; curb < linelen; curb++) {
>             bool thisbit = test_bit(cur + curb, todump);
>             fputc(thisbit ? '1' : '.', stderr);
>         }
>         fputc('\n', stderr);
>     }
> }
>
> Dave

Reviewed-by: Juan Quintela <quintela@redhat.com>


>
>
>> 
>> Later, Juan.
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

  reply	other threads:[~2015-07-13 10:15 UTC|newest]

Thread overview: 209+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-16 10:26 [Qemu-devel] [PATCH v7 00/42] Postcopy implementation Dr. David Alan Gilbert (git)
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 01/42] Start documenting how postcopy works Dr. David Alan Gilbert (git)
2015-06-17 11:42   ` Juan Quintela
2015-06-17 12:30     ` Dr. David Alan Gilbert
2015-06-18  7:50   ` Li, Liang Z
2015-06-18  8:10     ` Dr. David Alan Gilbert
2015-06-18  8:28     ` Paolo Bonzini
2015-06-19 17:52       ` Dr. David Alan Gilbert
2015-06-26  6:46   ` Yang Hongyang
2015-06-26  7:53     ` zhanghailiang
2015-06-26  8:00       ` Yang Hongyang
2015-06-26  8:10         ` Dr. David Alan Gilbert
2015-06-26  8:19           ` Yang Hongyang
2015-08-04  5:20   ` Amit Shah
2015-08-05 12:21     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 02/42] Provide runtime Target page information Dr. David Alan Gilbert (git)
2015-06-17 11:43   ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 03/42] Init page sizes in qtest Dr. David Alan Gilbert (git)
2015-06-17 11:49   ` Juan Quintela
2015-07-06  6:14   ` Amit Shah
2015-08-04  5:23   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 04/42] qemu_ram_block_from_host Dr. David Alan Gilbert (git)
2015-06-17 11:54   ` Juan Quintela
2015-07-10  8:36   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 05/42] Add qemu_get_buffer_less_copy to avoid copies some of the time Dr. David Alan Gilbert (git)
2015-06-17 11:57   ` Juan Quintela
2015-06-17 12:33     ` Dr. David Alan Gilbert
2015-07-13  9:08   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 06/42] Add wrapper for setting blocking status on a QEMUFile Dr. David Alan Gilbert (git)
2015-06-17 11:59   ` Juan Quintela
2015-06-17 12:34     ` Dr. David Alan Gilbert
2015-06-17 12:57       ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 07/42] ram_debug_dump_bitmap: Dump a migration bitmap as text Dr. David Alan Gilbert (git)
2015-06-17 12:17   ` Juan Quintela
2015-06-19 17:04     ` Dr. David Alan Gilbert
2015-07-13 10:15       ` Juan Quintela [this message]
2015-07-13  9:12   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 08/42] migrate_init: Call from savevm Dr. David Alan Gilbert (git)
2015-06-17 12:18   ` Juan Quintela
2015-07-13  9:13   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 09/42] Rename save_live_complete to save_live_complete_precopy Dr. David Alan Gilbert (git)
2015-06-17 12:20   ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 10/42] Return path: Open a return path on QEMUFile for sockets Dr. David Alan Gilbert (git)
2015-06-17 12:23   ` Juan Quintela
2015-06-17 17:07     ` Dr. David Alan Gilbert
2015-07-13 10:12   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 11/42] Return path: socket_writev_buffer: Block even on non-blocking fd's Dr. David Alan Gilbert (git)
2015-06-17 12:28   ` Juan Quintela
2015-06-19 17:18     ` Dr. David Alan Gilbert
2015-07-13 12:37   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 12/42] Migration commands Dr. David Alan Gilbert (git)
2015-06-17 12:31   ` Juan Quintela
2015-06-19 17:38     ` Dr. David Alan Gilbert
2015-07-13 12:45   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 13/42] Return path: Control commands Dr. David Alan Gilbert (git)
2015-06-17 12:49   ` Juan Quintela
2015-06-23 18:57     ` Dr. David Alan Gilbert
2015-07-13 12:55   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 14/42] Return path: Send responses from destination to source Dr. David Alan Gilbert (git)
2015-06-17 16:30   ` Juan Quintela
2015-06-19 18:42     ` Dr. David Alan Gilbert
2015-07-01  9:29       ` Juan Quintela
2015-08-06 12:18         ` Dr. David Alan Gilbert
2015-07-15  7:31   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 15/42] Return path: Source handling of return path Dr. David Alan Gilbert (git)
2015-07-13 10:29   ` Juan Quintela
2015-08-18 10:23     ` Dr. David Alan Gilbert
2015-07-15  7:50   ` Amit Shah
2015-07-16 11:32     ` Dr. David Alan Gilbert
2015-08-05  8:06   ` zhanghailiang
2015-08-18 10:45     ` Dr. David Alan Gilbert
2015-08-18 11:29       ` zhanghailiang
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 16/42] Rework loadvm path for subloops Dr. David Alan Gilbert (git)
2015-07-13 10:33   ` Juan Quintela
2015-07-15  9:34   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 17/42] Add migration-capability boolean for postcopy-ram Dr. David Alan Gilbert (git)
2015-06-16 15:43   ` Eric Blake
2015-06-16 15:58     ` Dr. David Alan Gilbert
2015-07-15  9:39       ` Amit Shah
2015-07-13 10:35   ` Juan Quintela
2015-07-15  9:40   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 18/42] Add wrappers and handlers for sending/receiving the postcopy-ram migration messages Dr. David Alan Gilbert (git)
2015-07-13 11:02   ` Juan Quintela
2015-07-20 10:13     ` Amit Shah
2015-08-26 14:48     ` Dr. David Alan Gilbert
2015-07-20 10:06   ` Amit Shah
2015-07-27  9:55     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 19/42] MIG_CMD_PACKAGED: Send a packaged chunk of migration stream Dr. David Alan Gilbert (git)
2015-07-13 11:07   ` Juan Quintela
2015-07-21  6:11   ` Amit Shah
2015-07-27 17:28     ` Dr. David Alan Gilbert
2015-08-04  5:27   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 20/42] Modify save_live_pending for postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:12   ` Juan Quintela
2015-07-31 16:13     ` Dr. David Alan Gilbert
2015-07-21  6:17   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 21/42] postcopy: OS support test Dr. David Alan Gilbert (git)
2015-07-13 11:20   ` Juan Quintela
2015-07-13 16:31     ` Dr. David Alan Gilbert
2015-07-21  7:29   ` Amit Shah
2015-07-27 17:38     ` Dr. David Alan Gilbert
2015-08-04  5:28   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 22/42] migrate_start_postcopy: Command to trigger transition to postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:23   ` Juan Quintela
2015-07-13 17:13     ` Dr. David Alan Gilbert
2015-07-13 18:07       ` Juan Quintela
2015-07-21  7:40         ` Amit Shah
2015-09-24  9:59           ` Dr. David Alan Gilbert
2015-09-24 14:20         ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 23/42] MIGRATION_STATUS_POSTCOPY_ACTIVE: Add new migration state Dr. David Alan Gilbert (git)
2015-07-13 11:27   ` Juan Quintela
2015-07-13 15:53     ` Dr. David Alan Gilbert
2015-07-13 16:26       ` Juan Quintela
2015-07-13 16:48         ` Dr. David Alan Gilbert
2015-07-13 18:05           ` Juan Quintela
2015-07-21 10:33   ` Amit Shah
2015-09-23 17:04     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 24/42] Add qemu_savevm_state_complete_postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:35   ` Juan Quintela
2015-07-13 15:33     ` Dr. David Alan Gilbert
2015-07-21 10:42   ` Amit Shah
2015-07-27 17:58     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 25/42] Postcopy: Maintain sentmap and calculate discard Dr. David Alan Gilbert (git)
2015-07-13 11:47   ` Juan Quintela
2015-09-15 17:01     ` Dr. David Alan Gilbert
2015-07-21 11:36   ` Amit Shah
2015-07-31 16:51     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 26/42] postcopy: Incoming initialisation Dr. David Alan Gilbert (git)
2015-07-13 12:04   ` Juan Quintela
2015-09-23 19:06     ` Dr. David Alan Gilbert
2015-07-22  6:19   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 27/42] postcopy: ram_enable_notify to switch on userfault Dr. David Alan Gilbert (git)
2015-07-13 12:10   ` Juan Quintela
2015-07-13 17:36     ` Dr. David Alan Gilbert
2015-07-23  5:22   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 28/42] Postcopy: Postcopy startup in migration thread Dr. David Alan Gilbert (git)
2015-07-13 12:56   ` Juan Quintela
2015-07-13 17:56     ` Dr. David Alan Gilbert
2015-07-13 18:09       ` Juan Quintela
2015-09-23 17:56         ` Dr. David Alan Gilbert
2015-07-23  5:53       ` Amit Shah
2015-07-23  5:55   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 29/42] Postcopy end in migration_thread Dr. David Alan Gilbert (git)
2015-07-13 13:15   ` Juan Quintela
2015-07-23  6:41     ` Amit Shah
2015-08-04 11:31     ` Dr. David Alan Gilbert
2015-07-23  6:41   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 30/42] Page request: Add MIG_RP_MSG_REQ_PAGES reverse command Dr. David Alan Gilbert (git)
2015-07-13 13:24   ` Juan Quintela
2015-08-06 14:15     ` Dr. David Alan Gilbert
2015-07-23  6:50   ` Amit Shah
2015-08-06 14:21     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 31/42] Page request: Process incoming page request Dr. David Alan Gilbert (git)
2015-07-14  9:18   ` Juan Quintela
2015-08-06 10:45     ` Dr. David Alan Gilbert
2015-10-20 10:29       ` Juan Quintela
2015-07-23 12:23   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 32/42] Page request: Consume pages off the post-copy queue Dr. David Alan Gilbert (git)
2015-07-14  9:40   ` Juan Quintela
2015-09-16 18:36     ` Dr. David Alan Gilbert
2015-07-27  6:05   ` Amit Shah
2015-09-16 18:48     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 33/42] postcopy_ram.c: place_page and helpers Dr. David Alan Gilbert (git)
2015-07-14 10:05   ` Juan Quintela
2015-07-27  6:11     ` Amit Shah
2015-09-23 16:45     ` Dr. David Alan Gilbert
2015-07-27  6:11   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 34/42] Postcopy: Use helpers to map pages during migration Dr. David Alan Gilbert (git)
2015-07-14 12:34   ` Juan Quintela
2015-07-17 17:31     ` Dr. David Alan Gilbert
2015-07-27  7:39   ` Amit Shah
2015-08-06 11:22     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 35/42] Don't sync dirty bitmaps in postcopy Dr. David Alan Gilbert (git)
2015-07-14 12:36   ` Juan Quintela
2015-07-14 13:13     ` Dr. David Alan Gilbert
2015-07-27  7:43   ` Amit Shah
2015-07-31  9:50     ` Dr. David Alan Gilbert
2015-08-04  5:46       ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 36/42] Host page!=target page: Cleanup bitmaps Dr. David Alan Gilbert (git)
2015-07-14 15:01   ` Juan Quintela
2015-07-31 15:53     ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 37/42] Postcopy; Handle userfault requests Dr. David Alan Gilbert (git)
2015-07-14 15:10   ` Juan Quintela
2015-07-14 15:15     ` Dr. David Alan Gilbert
2015-07-14 15:25       ` Juan Quintela
2015-07-27 14:29   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 38/42] Start up a postcopy/listener thread ready for incoming page data Dr. David Alan Gilbert (git)
2015-07-14 15:12   ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 39/42] postcopy: Wire up loadvm_postcopy_handle_ commands Dr. David Alan Gilbert (git)
2015-07-14 15:14   ` Juan Quintela
2015-07-28  5:53   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 40/42] End of migration for postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:15   ` Juan Quintela
2015-07-28  5:55   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 41/42] Disable mlock around incoming postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:22   ` Juan Quintela
2015-07-28  6:02     ` Amit Shah
2015-07-28 11:32       ` Juan Quintela
2015-08-06 14:55         ` Dr. David Alan Gilbert
2015-08-07  3:05           ` zhanghailiang
2015-09-24 10:36     ` Dr. David Alan Gilbert
2015-07-28  6:02   ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 42/42] Inhibit ballooning during postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:24   ` Juan Quintela
2015-07-28  6:15   ` Amit Shah
2015-07-28  9:08     ` Dr. David Alan Gilbert
2015-07-28 10:01       ` Amit Shah
2015-07-28 11:16         ` Dr. David Alan Gilbert
2015-07-28  6:21 ` [Qemu-devel] [PATCH v7 00/42] Postcopy implementation Amit Shah

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