Lines Matching refs:cache
2 nice if you could use them as cache... Hence bcache.
21 Writeback caching can use most of the cache for buffering writes - writing
30 thus entirely bypass the cache.
33 from disk or invalidating cache entries. For unrecoverable errors (meta data
35 in the cache it first disables writeback caching and waits for all dirty data
39 You'll need make-bcache from the bcache-tools repository. Both the cache device
45 you format your backing devices and cache device at the same time, you won't
57 device, it'll be running in passthrough mode until you attach it to a cache.
78 cache set shows up as /sys/fs/bcache/<UUID>
82 After your cache device and backing device are registered, the backing device
83 must be attached to your cache set to enable caching. Attaching a backing
84 device to a cache set is done thusly, with the UUID of the cache set in
90 your bcache devices. If a backing device has data in a cache somewhere, the
91 /dev/bcache<N> device won't be created until the cache shows up - particularly
94 If you're booting up and your cache device is gone and never coming back, you
103 The backing device will still use that cache set if it shows up in the future,
105 cache, don't expect the filesystem to be recoverable - you will have massive
110 Bcache tries to transparently handle IO errors to/from the cache device without
112 configurable, and defaults to 0) it shuts down the cache device and switches all
115 - For reads from the cache, if they error we just retry the read from the
118 - For writethrough writes, if the write to the cache errors we just switch to
119 invalidating the data at that lba in the cache (i.e. the same thing we do for
120 a write that bypasses the cache)
124 that skips the cache so we don't have to error the write.
147 By default, bcache doesn't cache everything. It tries to skip sequential IO -
150 accessed data out of your cache.
152 But if you want to benchmark reads from cache, and you start out with fio
161 - Traffic's still going to the spindle/still getting cache misses
168 To avoid that bcache tracks latency to the cache device, and gradually
174 # echo 0 > /sys/fs/bcache/<cache set>/congested_read_threshold_us
175 # echo 0 > /sys/fs/bcache/<cache set>/congested_write_threshold_us
179 - Still getting cache misses, of the same data
182 the way cache coherency is handled for cache misses. If a btree node is full,
183 a cache miss won't be able to insert a key for the new data and the data
184 won't be written to the cache.
190 benchmarking, if you're trying to warm the cache by reading a bunch of data
193 Solution: warm the cache by doing writes, or use the testing branch (there's
202 Echo the UUID of a cache set to this file to enable caching.
212 Write to this file to detach from a cache set. If there is dirty data in the
213 cache, it will be flushed first.
216 Amount of dirty data for this backing device in the cache. Continuously
217 updated unlike the cache set's version, but may be slightly off.
224 1M, it will round cache miss reads up to that size, but without overlapping
225 existing cache entries.
232 A sequential IO will bypass the cache once it passes this threshold; the
246 no cache: Has never been attached to a cache set.
248 clean: Part of a cache set, and there is no cached dirty data.
250 dirty: Part of a cache set, and there is cached dirty data.
253 dirty data cached but the cache set was unavailable; whatever data was on the
261 When dirty data is written to the cache and it previously did not contain
266 If nonzero, bcache tries to keep around this percentage of the cache dirty by
277 still be added to the cache until it is mostly full; only meant for
284 aggregated in the cache set directory as well.
287 Amount of IO (both reads and writes) that has bypassed the cache
297 Hits and misses for IO that is intended to skip the cache are still counted,
301 Counts instances where data was going to be inserted into the cache from a
302 cache miss, but raced with a write and data was already present (usually 0
303 since the synchronization for cache misses was rewritten)
319 Block size of the cache devices.
322 Amount of memory currently used by the btree cache
327 cache<0..n>
328 Symlink to each of the cache devices comprising this cache set.
331 Percentage of cache device which doesn't contain dirty data, and could
337 Clears the statistics associated with this cache
340 Amount of dirty data is in the cache (updated when garbage collection runs).
344 provisioned volume backed by the cache set.
348 These determines how many errors we accept before disabling the cache.
350 reaches io_error_limit dirty data is written out and the cache is disabled.
353 Journal writes will delay for up to this many milliseconds, unless a cache
361 Write to this file to shut down the cache set - waits until all attached
368 Detaches all backing devices and closes the cache devices; if dirty data is
390 Longest chain in the btree node cache's hash table
393 Counts instances where while data was being read from the cache, the bucket
424 artificially reduce the size of the cache at runtime. Mostly for testing
437 Total buckets in this cache
440 Statistics about how recently data in the cache has been accessed.
442 the cache that doesn't contain any data. Metadata is bcache's
443 metadata overhead. Average is the average priority of cache buckets.
447 Sum of all data that has been written to the cache; comparison with