Messages in this thread | | | Date | Fri, 8 Mar 2019 11:46:57 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH v5 07/10] perf record: implement -z,--compression_level=n option and compression |
| |
On Thu, Mar 07, 2019 at 06:26:47PM +0300, Alexey Budankov wrote: > > On 07.03.2019 15:14, Jiri Olsa wrote: > > On Thu, Mar 07, 2019 at 11:39:46AM +0300, Alexey Budankov wrote: > >> > >> On 05.03.2019 15:25, Jiri Olsa wrote: > >>> On Fri, Mar 01, 2019 at 06:58:32PM +0300, Alexey Budankov wrote: > >>> > >>> SNIP > >>> > >>>> > >>>> /* > >>>> * Increment md->refcount to guard md->data[idx] buffer > >>>> @@ -350,7 +357,7 @@ int perf_mmap__aio_push(struct perf_mmap *md, void *to, int idx, > >>>> md->prev = head; > >>>> perf_mmap__consume(md); > >>>> > >>>> - rc = push(to, &md->aio.cblocks[idx], md->aio.data[idx], size0 + size, *off); > >>>> + rc = push(to, md->aio.data[idx], size0 + size, *off, &md->aio.cblocks[idx]); > >>>> if (!rc) { > >>>> *off += size0 + size; > >>>> } else { > >>>> @@ -556,13 +563,15 @@ int perf_mmap__read_init(struct perf_mmap *map) > >>>> } > >>>> > >>>> int perf_mmap__push(struct perf_mmap *md, void *to, > >>>> - int push(struct perf_mmap *map, void *to, void *buf, size_t size)) > >>>> + int push(struct perf_mmap *map, void *to, void *buf, size_t size), > >>>> + perf_mmap__compress_fn_t compress, void *comp_data) > >>>> { > >>>> u64 head = perf_mmap__read_head(md); > >>>> unsigned char *data = md->base + page_size; > >>>> unsigned long size; > >>>> void *buf; > >>>> int rc = 0; > >>>> + size_t mmap_len = perf_mmap__mmap_len(md); > >>>> > >>>> rc = perf_mmap__read_init(md); > >>>> if (rc < 0) > >>>> @@ -574,7 +583,10 @@ int perf_mmap__push(struct perf_mmap *md, void *to, > >>>> buf = &data[md->start & md->mask]; > >>>> size = md->mask + 1 - (md->start & md->mask); > >>>> md->start += size; > >>>> - > >>>> + if (compress) { > >>>> + size = compress(comp_data, md->data, mmap_len, buf, size); > >>>> + buf = md->data; > >>>> + } > >>>> if (push(md, to, buf, size) < 0) { > >>>> rc = -1; > >>>> goto out; > >>> > >>> when we discussed the compress callback should be another layer > >>> in perf_mmap__push I was thinking more of the layered/fifo design, > >>> like: > >>> > >>> normaly we call: > >>> > >>> perf_mmap__push(... push = record__pushfn ...) > >>> -> reads mmap data and calls push(data), which translates as: > >>> > >>> record__pushfn(data); > >>> - which stores the data > >>> > >>> > >>> for compressed it'd be: > >>> > >>> perf_mmap__push(... push = compressed_push ...) > >>> > >>> -> reads mmap data and calls push(data), which translates as: > >>> > >>> compressed_push(data) > >>> -> reads data, compresses them and calls, next push callback in line: > >>> > >>> record__pushfn(data) > >>> - which stores the data > >>> > >>> > >>> there'd need to be the logic for compressed_push to > >>> remember the 'next push' function > >> > >> That is suboptimal for AIO. Also compression is an independent operation that > >> could be applied on any of push stages you mean. > > > > not sure what you mean by suboptimal, but I think > > that it can still happen in subsequent push callback > > > >> > >>> > >>> but I think this was the original idea behind the > >>> perf_mmap__push -> it gets the data and pushes them for > >>> the next processing.. it should stay as simple as that > >> > >> Agree on keeping simplicity and, at the moment, there is no any push to the next > >> processing in the code so provided implementation fits as for serial as for AIO > >> at the same time sticking to simplicity as much as possibly. If you see something > >> that would fit better please speak up and share. > > > > I have to insist that perf_mmap__push stays untouched > > and we do other processing in the push callbacks > > What is about perf_mmap__aio_push()? > > Without compression it does > memcpy(), memcpy(), aio_push() > > With compression its does > memcpy_with_compression(), memcpy_with_compression(), aio_push()
so to be on the same page.. normal processing without compression is:
perf_mmap__push does: push(mmap buf) record__pushfn record__write write(buf)
perf_mmap__aio_push does: memcpy(aio buf, mmap buf) push(aio buf) record__aio_pushfn record__aio_write aio_write(aio buf)
and for compression it would be:
perf_mmap__push does: push(mmap buf) compress_push memcpy(compress buffer, mmapbuf) EXTRA copy record__pushfn record__write write(buf)
perf_mmap__aio_push does: memcpy(aio buf, mmap buf) memcpy(compress buffer, mmapbuf) EXTRA copy push(aio buf) record__aio_pushfn record__aio_write aio_write(aio buf)
side note: that actualy makes me think why do we even have perf_mmap__aio_push, it looks like we could copy the buf in the callback push function with no harm?
so.. there's one extra memcpy for compression, is it right? I might miss some part which makes this scheme unusable..
thanks, jirka
| |