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[Qemu-devel] Re: [PATCH 1/2] block: Add wr_highest_sector blockstat
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] Re: [PATCH 1/2] block: Add wr_highest_sector blockstat |
Date: |
Thu, 29 Apr 2010 12:00:45 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 |
Am 28.04.2010 19:31, schrieb Luiz Capitulino:
> On Wed, 28 Apr 2010 17:56:20 +0200
> Kevin Wolf <address@hidden> wrote:
>
>> This adds the wr_highest_sector blockstat which implements what is generally
>> known as the high watermark. It is the highest offset of a sector written to
>> the respective BlockDriverState since it has been opened.
>>
>> The query-blockstat QMP command is extended to add this value to the result,
>> and also to add the statistics of the underlying protocol in a new "parent"
>> field. Note that to get the "high watermark" of a qcow2 image, you need to
>> look
>> into the wr_highest_sector field of the parent (which can be a file, a
>> host_device, ...). The wr_highest_sector of the qcow2 BlockDriverState itself
>> is the highest offset on the _virtual_ disk that the guest has written to.
>>
>> Signed-off-by: Kevin Wolf <address@hidden>
>> ---
>> block.c | 76
>> +++++++++++++++++++++++++++++++++++++++++++++++-----------
>> block_int.h | 1 +
>> 2 files changed, 62 insertions(+), 15 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index 91fecab..b75cef2 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -880,6 +880,10 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num,
>> set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
>> }
>>
>> + if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
>> + bs->wr_highest_sector = sector_num + nb_sectors - 1;
>> + }
>> +
>> return drv->bdrv_write(bs, sector_num, buf, nb_sectors);
>> }
>>
>> @@ -1523,6 +1527,10 @@ static void bdrv_stats_iter(QObject *data, void
>> *opaque)
>> qdict_get_int(qdict, "wr_bytes"),
>> qdict_get_int(qdict, "rd_operations"),
>> qdict_get_int(qdict, "wr_operations"));
>> + if (qdict_haskey(qdict, "parent")) {
>> + QObject *parent = qdict_get(qdict, "parent");
>> + bdrv_stats_iter(parent, mon);
>> + }
>> }
>>
>> void bdrv_stats_print(Monitor *mon, const QObject *data)
>> @@ -1530,6 +1538,34 @@ void bdrv_stats_print(Monitor *mon, const QObject
>> *data)
>> qlist_iter(qobject_to_qlist(data), bdrv_stats_iter, mon);
>> }
>>
>> +static QObject* bdrv_info_stats_bs(BlockDriverState *bs)
>> +{
>> + QObject *res;
>> + QObject *parent = NULL;
>> +
>> + if (bs->file) {
>> + parent = bdrv_info_stats_bs(bs->file);
>> + }
>
> Doesn't build, I guess you meant 'backing_hd'.
The patch is against git://repo.or.cz/qemu/kevin.git block, not master
(like most block related patches lately).
backing_hd is for qcow base images, so that's a different thing.
>> +
>> + res = qobject_from_jsonf("{ 'device': %s, 'stats': {"
>> + "'rd_bytes': %" PRId64 ","
>> + "'wr_bytes': %" PRId64 ","
>> + "'rd_operations': %" PRId64 ","
>> + "'wr_operations': %" PRId64 ","
>> + "'wr_highest_offset': %" PRId64
>> + "} }",
>> + bs->device_name,
>> + bs->rd_bytes, bs->wr_bytes,
>> + bs->rd_ops, bs->wr_ops,
>> + bs->wr_highest_sector * 512);
>> + if (parent) {
>> + QDict *dict = qobject_to_qdict(res);
>> + qdict_put_obj(dict, "parent", parent);
>> + }
>> +
>> + return res;
>> +}
>> +
>> /**
>> * bdrv_info_stats(): show block device statistics
>> *
>> @@ -1544,19 +1580,34 @@ void bdrv_stats_print(Monitor *mon, const QObject
>> *data)
>> * - "wr_bytes": bytes written
>> * - "rd_operations": read operations
>> * - "wr_operations": write operations
>> - *
>> + * - "wr_highest_offset": Highest offset of a sector written since the
>> + * BlockDriverState has been opened
>> + * - "parent": Contains recursively the statistics of the underlying
>> + * protocol (e.g. the host file for a qcow2 image). If there is no
>> + * underlying protocol, this field is omitted.
>
> Looks like you are not pushing 'protocol', we already have 'format'
> though (not sure if they overlap).
You're talking about a new key 'protocol'? I'm not sure what it should
describe, to be honest.
> Also, 'device' is "" for 'parent'. You should consider not pushing the
> key in this case (and noting that it's optional in the doc above).
Ok, will change that for v2.
Kevin