[Libguestfs] [nbdkit PATCH v2 21/24] stats: Implement .cache

In the stats filter, all we need to do is copy-and-paste existing per-command stats to one more class of commands (well, technically, this isn't enabled until a later patch flips the default for .can_cache to pass-through). Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- filters/stats/stats.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/filters/stats/stats.c b/filters/stats/stats.c index 785cce6..037fc61 100644 --- a/filters/stats/stats.c +++ b/filters/stats/stats.c @@ -61,6 +61,7 @@ static uint64_t pwrite_ops, pwrite_bytes; static uint64_t trim_ops, trim_bytes; static uint64_t zero_ops, zero_bytes; static uint64_t extents_ops, extents_bytes; +static uint64_t cache_ops, cache_bytes; static inline double calc_bps (uint64_t bytes, int64_t usecs) @@ -88,6 +89,9 @@ print_stats (int64_t usecs) if (extents_ops > 0) fprintf (fp, "extents: %" PRIu64 " ops, %" PRIu64 " bytes, %g bits/s\n", extents_ops, extents_bytes, calc_bps (extents_bytes, usecs)); + if (cache_ops > 0) + fprintf (fp, "cache: %" PRIu64 " ops, %" PRIu64 " bytes, %g bits/s\n", + cache_ops, cache_bytes, calc_bps (cache_bytes, usecs)); fflush (fp); } @@ -246,6 +250,24 @@ stats_extents (struct nbdkit_next_ops *next_ops, void *nxdata, return r; } +/* Cache. */ +static int +stats_cache (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, + uint32_t count, uint64_t offset, uint32_t flags, + int *err) +{ + int r; + + r = next_ops->cache (nxdata, count, offset, flags, err); + if (r == 0) { + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + cache_ops++; + cache_bytes += count; + } + return r; +} + static struct nbdkit_filter filter = { .name = "stats", .longname = "nbdkit stats filter", @@ -258,6 +280,7 @@ static struct nbdkit_filter filter = { .trim = stats_trim, .zero = stats_zero, .extents = stats_extents, + .cache = stats_cache, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1