diff options
Diffstat (limited to 'src/feature/dircache/dircache.c')
| -rw-r--r-- | src/feature/dircache/dircache.c | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/src/feature/dircache/dircache.c b/src/feature/dircache/dircache.c index e8cb284165..2f8a281cd1 100644 --- a/src/feature/dircache/dircache.c +++ b/src/feature/dircache/dircache.c @@ -294,19 +294,22 @@ client_likes_consensus(const struct consensus_cache_entry_t *ent, /** Return the compression level we should use for sending a compressed * response of size <b>n_bytes</b>. */ STATIC compression_level_t -choose_compression_level(ssize_t n_bytes) +choose_compression_level(void) { - if (! have_been_under_memory_pressure()) { - return HIGH_COMPRESSION; /* we have plenty of RAM. */ - } else if (n_bytes < 0) { - return HIGH_COMPRESSION; /* unknown; might be big. */ - } else if (n_bytes < 1024) { - return LOW_COMPRESSION; - } else if (n_bytes < 2048) { - return MEDIUM_COMPRESSION; - } else { - return HIGH_COMPRESSION; - } + /* This is the compression level choice for a stream. + * + * We always return LOW because this compression is done in the main thread + * thus we save CPU time as much as possible, and it is also done more than + * background compression for document we serve pre-compressed. + * + * GZip highest compression level (9) gives us a ratio of 49.72% + * Zstd lowest compression level (1) gives us a ratio of 47.38% + * + * Thus, as the network moves more and more to use Zstd when requesting + * directory documents that are not pre-cached, even at the + * lowest level, we still gain over GZip and thus help with load and CPU + * time on the network. */ + return LOW_COMPRESSION; } /** Information passed to handle a GET request. */ @@ -1044,7 +1047,7 @@ handle_get_status_vote(dir_connection_t *conn, const get_handler_args_t *args) if (smartlist_len(items)) { if (compress_method != NO_METHOD) { conn->compress_state = tor_compress_new(1, compress_method, - choose_compression_level(estimated_len)); + choose_compression_level()); SMARTLIST_FOREACH(items, const char *, c, connection_buf_add_compress(c, strlen(c), conn, 0)); connection_buf_add_compress("", 0, conn, 1); @@ -1109,7 +1112,7 @@ handle_get_microdesc(dir_connection_t *conn, const get_handler_args_t *args) if (compress_method != NO_METHOD) conn->compress_state = tor_compress_new(1, compress_method, - choose_compression_level(size_guess)); + choose_compression_level()); const int initial_flush_result = connection_dirserv_flushed_some(conn); tor_assert_nonfatal(initial_flush_result == 0); @@ -1204,7 +1207,7 @@ handle_get_descriptor(dir_connection_t *conn, const get_handler_args_t *args) write_http_response_header(conn, -1, compress_method, cache_lifetime); if (compress_method != NO_METHOD) conn->compress_state = tor_compress_new(1, compress_method, - choose_compression_level(size_guess)); + choose_compression_level()); clear_spool = 0; /* Prime the connection with some data. */ int initial_flush_result = connection_dirserv_flushed_some(conn); @@ -1301,7 +1304,7 @@ handle_get_keys(dir_connection_t *conn, const get_handler_args_t *args) 60*60); if (compress_method != NO_METHOD) { conn->compress_state = tor_compress_new(1, compress_method, - choose_compression_level(len)); + choose_compression_level()); SMARTLIST_FOREACH(certs, authority_cert_t *, c, connection_buf_add_compress( c->cache_info.signed_descriptor_body, |