From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by passt.top (Postfix, from userid 1000) id 3E20C5A0625; Mon, 08 Dec 2025 08:20:24 +0100 (CET) From: Stefano Brivio To: passt-dev@passt.top Subject: [PATCH v3 02/10] tcp: Change usage factor of sending buffer in tcp_get_sndbuf() to 75% Date: Mon, 8 Dec 2025 08:20:15 +0100 Message-ID: <20251208072024.3884137-3-sbrivio@redhat.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251208072024.3884137-1-sbrivio@redhat.com> References: <20251208072024.3884137-1-sbrivio@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: FKCDJ2GPSTG6EOFH7Z7I7IONLXF2BEVW X-Message-ID-Hash: FKCDJ2GPSTG6EOFH7Z7I7IONLXF2BEVW X-MailFrom: sbrivio@passt.top X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Max Chernoff , David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Now that we have a new clamped_scale() function, which makes it simple to specify a precise usage factor, change the amount of sending buffer we want to use at and above 4 MiB: 75% looks perfectly safe. Signed-off-by: Stefano Brivio --- tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tcp.c b/tcp.c index 026546a..37aceed 100644 --- a/tcp.c +++ b/tcp.c @@ -773,7 +773,7 @@ static void tcp_rtt_dst_check(const struct tcp_tap_conn *conn, } /** - * tcp_get_sndbuf() - Get, scale SO_SNDBUF between thresholds (1 to 0.5 usage) + * tcp_get_sndbuf() - Get, scale SO_SNDBUF between thresholds (1 to 0.75 usage) * @conn: Connection pointer */ static void tcp_get_sndbuf(struct tcp_tap_conn *conn) @@ -788,7 +788,7 @@ static void tcp_get_sndbuf(struct tcp_tap_conn *conn) return; } - v = clamped_scale(sndbuf, sndbuf, SNDBUF_SMALL, SNDBUF_BIG, 50); + v = clamped_scale(sndbuf, sndbuf, SNDBUF_SMALL, SNDBUF_BIG, 75); SNDBUF_SET(conn, MIN(INT_MAX, v)); } -- 2.43.0