From nobody Sat Nov 23 19:21:26 2024 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3459C145B16; Mon, 11 Nov 2024 04:57:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731301070; cv=none; b=MITaAj+s6cGM9WOSA1S/LQ1bQQ5kNks0S0wJij7HeZ7+FOb+MHyksZbFWT6CBkatuQwURodGLPEUzTR7601/ry9Qyu+usfqaD6/ykdMvJ258jdMs8F+Ppfwre9vyDN1enR2TLEko4+bxO369tqTapOvBjHVlOS/9oqtd+RW4opM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731301070; c=relaxed/simple; bh=sfTgdTJh1p7JRgOiYF2XlibB9miS7yTgFim2KFUF8HY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=sb91EtKorZmqFNxTdx7CnUEMrjx/ZXa2DWifHuBCWl/9zN+KqPtxgQXhwBsXeYsRbOe2idjm9AbOAoS3iOyW3KLwezUMzxG/T5+hbbTeIs5nkZX09l1rarJxrtnR1dvJvHHC2SqlYF3JAJ3GHTKuOxI+QQ6VrSraNdFJOQx0o4Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=pxqv4V/q; arc=none smtp.client-ip=220.197.31.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="pxqv4V/q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=SHVIa l6tBpBpXY3unYv6Gce9rTF7SHEzPbAB03hJXec=; b=pxqv4V/ql9w3wBNIw0JfB FfWDCs/6VtjqHeL0nNgeXSTOAOdabMlQIcOKXefjRnT3wwwU1lU+aiWR8DEIAJXC RSyZUf6E1gwS6IFPJbwQ8kS8yDzhHRvp9uTVJWJYfj4JFr63towidZ0Dht9EoWmR o2kNqbtk5eI8UvRM8kjPi0= Received: from localhost.localdomain (unknown [111.35.191.191]) by gzsmtp3 (Coremail) with SMTP id PigvCgC3uS59jjFnxgklBw--.36494S4; Mon, 11 Nov 2024 12:57:02 +0800 (CST) From: David Wang <00107082@163.com> To: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Wang <00107082@163.com> Subject: [PATCH] net/ipv4/proc: Avoid usage for seq_printf() when reading /proc/net/snmp Date: Mon, 11 Nov 2024 12:56:23 +0800 Message-Id: <20241111045623.10229-1-00107082@163.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: PigvCgC3uS59jjFnxgklBw--.36494S4 X-Coremail-Antispam: 1Uf129KBjvJXoW3Xr13Zr4xtw1UKw18Gr4fAFb_yoWfZr1kpa y3A34qgr1xJr1Utrsrta1vg3WrWF93AFy2g3ZrGa10y3W5ZrZ5Can3WrW2qF45GFyvqrW5 XF4DWFy7G398tw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pELZ2sUUUUU= X-CM-SenderInfo: qqqrilqqysqiywtou0bp/xtbB0gWUqmcxiOtsiwAAs7 Content-Type: text/plain; charset="utf-8" seq_printf() is costy, when reading /proc/net/snmp, profiling indicates seq_printf() takes more than 50% samples of snmp_seq_show(): snmp_seq_show(97.751% 158722/162373) snmp_seq_show_tcp_udp.isra.0(40.017% 63515/158722) seq_printf(83.451% 53004/63515) seq_write(1.170% 743/63515) _find_next_bit(0.727% 462/63515) ... seq_printf(24.762% 39303/158722) snmp_seq_show_ipstats.isra.0(21.487% 34104/158722) seq_printf(85.788% 29257/34104) _find_next_bit(0.331% 113/34104) seq_write(0.235% 80/34104) ... icmpmsg_put(7.235% 11483/158722) seq_printf(41.714% 4790/11483) seq_write(2.630% 302/11483) ... Time for a million rounds of stress reading /proc/net/snmp: real 0m24.323s user 0m0.293s sys 0m23.679s On average, reading /proc/net/snmp takes 0.023ms. With this patch, extra costs of seq_printf() is avoided, and a million rounds of reading /proc/net/snmp now takes only ~15.853s: real 0m16.386s user 0m0.280s sys 0m15.853s On average, one read takes 0.015ms, a ~40% improvement. Signed-off-by: David Wang <00107082@163.com> --- net/ipv4/proc.c | 116 ++++++++++++++++++++++++++++-------------------- 1 file changed, 69 insertions(+), 47 deletions(-) diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 40053a02bae1..3a4586103b5e 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -315,13 +315,14 @@ static void icmpmsg_put_line(struct seq_file *seq, un= signed long *vals, =20 if (count) { seq_puts(seq, "\nIcmpMsg:"); - for (j =3D 0; j < count; ++j) - seq_printf(seq, " %sType%u", - type[j] & 0x100 ? "Out" : "In", - type[j] & 0xff); + for (j =3D 0; j < count; ++j) { + seq_putc(seq, ' '); + seq_puts(seq, type[j] & 0x100 ? "Out" : "In"); + seq_put_decimal_ull(seq, "Type", type[j] & 0xff); + } seq_puts(seq, "\nIcmpMsg:"); for (j =3D 0; j < count; ++j) - seq_printf(seq, " %lu", vals[j]); + seq_put_decimal_ull(seq, " ", vals[j]); } } =20 @@ -358,26 +359,35 @@ static void icmp_put(struct seq_file *seq) atomic_long_t *ptr =3D net->mib.icmpmsg_statistics->mibs; =20 seq_puts(seq, "\nIcmp: InMsgs InErrors InCsumErrors"); - for (i =3D 0; icmpmibmap[i].name; i++) - seq_printf(seq, " In%s", icmpmibmap[i].name); + for (i =3D 0; icmpmibmap[i].name; i++) { + seq_puts(seq, " In"); + seq_puts(seq, icmpmibmap[i].name); + } seq_puts(seq, " OutMsgs OutErrors OutRateLimitGlobal OutRateLimitHost"); + for (i =3D 0; icmpmibmap[i].name; i++) { + seq_puts(seq, " Out"); + seq_puts(seq, icmpmibmap[i].name); + } + seq_puts(seq, "\nIcmp:"); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_INMSGS)); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_INERRORS)); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_CSUMERRORS)); for (i =3D 0; icmpmibmap[i].name; i++) - seq_printf(seq, " Out%s", icmpmibmap[i].name); - seq_printf(seq, "\nIcmp: %lu %lu %lu", - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_INMSGS), - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_INERRORS), - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_CSUMERRORS)); + seq_put_decimal_ull(seq, " ", atomic_long_read(ptr + icmpmibmap[i].index= )); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_OUTMSGS)); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_OUTERRORS)); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_RATELIMITGLOBAL)= ); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_RATELIMITHOST)); for (i =3D 0; icmpmibmap[i].name; i++) - seq_printf(seq, " %lu", - atomic_long_read(ptr + icmpmibmap[i].index)); - seq_printf(seq, " %lu %lu %lu %lu", - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_OUTMSGS), - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_OUTERRORS), - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_RATELIMITGLOBAL), - snmp_fold_field(net->mib.icmp_statistics, ICMP_MIB_RATELIMITHOST)); - for (i =3D 0; icmpmibmap[i].name; i++) - seq_printf(seq, " %lu", - atomic_long_read(ptr + (icmpmibmap[i].index | 0x100))); + seq_put_decimal_ull(seq, " ", + atomic_long_read(ptr + (icmpmibmap[i].index | 0x100))); } =20 /* @@ -392,8 +402,10 @@ static int snmp_seq_show_ipstats(struct seq_file *seq,= void *v) memset(buff64, 0, IPSTATS_MIB_MAX * sizeof(u64)); =20 seq_puts(seq, "Ip: Forwarding DefaultTTL"); - for (i =3D 0; snmp4_ipstats_list[i].name; i++) - seq_printf(seq, " %s", snmp4_ipstats_list[i].name); + for (i =3D 0; snmp4_ipstats_list[i].name; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_ipstats_list[i].name); + } =20 seq_printf(seq, "\nIp: %d %d", IPV4_DEVCONF_ALL_RO(net, FORWARDING) ? 1 : 2, @@ -404,7 +416,7 @@ static int snmp_seq_show_ipstats(struct seq_file *seq, = void *v) net->mib.ip_statistics, offsetof(struct ipstats_mib, syncp)); for (i =3D 0; snmp4_ipstats_list[i].name; i++) - seq_printf(seq, " %llu", buff64[i]); + seq_put_decimal_ull(seq, " ", buff64[i]); =20 return 0; } @@ -418,8 +430,10 @@ static int snmp_seq_show_tcp_udp(struct seq_file *seq,= void *v) memset(buff, 0, TCPUDP_MIB_MAX * sizeof(unsigned long)); =20 seq_puts(seq, "\nTcp:"); - for (i =3D 0; snmp4_tcp_list[i].name; i++) - seq_printf(seq, " %s", snmp4_tcp_list[i].name); + for (i =3D 0; snmp4_tcp_list[i].name; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_tcp_list[i].name); + } =20 seq_puts(seq, "\nTcp:"); snmp_get_cpu_field_batch(buff, snmp4_tcp_list, @@ -429,7 +443,7 @@ static int snmp_seq_show_tcp_udp(struct seq_file *seq, = void *v) if (snmp4_tcp_list[i].entry =3D=3D TCP_MIB_MAXCONN) seq_printf(seq, " %ld", buff[i]); else - seq_printf(seq, " %lu", buff[i]); + seq_put_decimal_ull(seq, " ", buff[i]); } =20 memset(buff, 0, TCPUDP_MIB_MAX * sizeof(unsigned long)); @@ -437,11 +451,13 @@ static int snmp_seq_show_tcp_udp(struct seq_file *seq= , void *v) snmp_get_cpu_field_batch(buff, snmp4_udp_list, net->mib.udp_statistics); seq_puts(seq, "\nUdp:"); - for (i =3D 0; snmp4_udp_list[i].name; i++) - seq_printf(seq, " %s", snmp4_udp_list[i].name); + for (i =3D 0; snmp4_udp_list[i].name; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_udp_list[i].name); + } seq_puts(seq, "\nUdp:"); for (i =3D 0; snmp4_udp_list[i].name; i++) - seq_printf(seq, " %lu", buff[i]); + seq_put_decimal_ull(seq, " ", buff[i]); =20 memset(buff, 0, TCPUDP_MIB_MAX * sizeof(unsigned long)); =20 @@ -449,11 +465,13 @@ static int snmp_seq_show_tcp_udp(struct seq_file *seq= , void *v) seq_puts(seq, "\nUdpLite:"); snmp_get_cpu_field_batch(buff, snmp4_udp_list, net->mib.udplite_statistics); - for (i =3D 0; snmp4_udp_list[i].name; i++) - seq_printf(seq, " %s", snmp4_udp_list[i].name); + for (i =3D 0; snmp4_udp_list[i].name; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_udp_list[i].name); + } seq_puts(seq, "\nUdpLite:"); for (i =3D 0; snmp4_udp_list[i].name; i++) - seq_printf(seq, " %lu", buff[i]); + seq_put_decimal_ull(seq, " ", buff[i]); =20 seq_putc(seq, '\n'); return 0; @@ -483,8 +501,10 @@ static int netstat_seq_show(struct seq_file *seq, void= *v) int i; =20 seq_puts(seq, "TcpExt:"); - for (i =3D 0; i < tcp_cnt; i++) - seq_printf(seq, " %s", snmp4_net_list[i].name); + for (i =3D 0; i < tcp_cnt; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_net_list[i].name); + } =20 seq_puts(seq, "\nTcpExt:"); buff =3D kzalloc(max(tcp_cnt * sizeof(long), ip_cnt * sizeof(u64)), @@ -493,16 +513,18 @@ static int netstat_seq_show(struct seq_file *seq, voi= d *v) snmp_get_cpu_field_batch(buff, snmp4_net_list, net->mib.net_statistics); for (i =3D 0; i < tcp_cnt; i++) - seq_printf(seq, " %lu", buff[i]); + seq_put_decimal_ull(seq, " ", buff[i]); } else { for (i =3D 0; i < tcp_cnt; i++) - seq_printf(seq, " %lu", - snmp_fold_field(net->mib.net_statistics, - snmp4_net_list[i].entry)); + seq_put_decimal_ull(seq, " ", + snmp_fold_field(net->mib.net_statistics, + snmp4_net_list[i].entry)); } seq_puts(seq, "\nIpExt:"); - for (i =3D 0; i < ip_cnt; i++) - seq_printf(seq, " %s", snmp4_ipextstats_list[i].name); + for (i =3D 0; i < ip_cnt; i++) { + seq_putc(seq, ' '); + seq_puts(seq, snmp4_ipextstats_list[i].name); + } =20 seq_puts(seq, "\nIpExt:"); if (buff) { @@ -513,13 +535,13 @@ static int netstat_seq_show(struct seq_file *seq, voi= d *v) net->mib.ip_statistics, offsetof(struct ipstats_mib, syncp)); for (i =3D 0; i < ip_cnt; i++) - seq_printf(seq, " %llu", buff64[i]); + seq_put_decimal_ull(seq, " ", buff64[i]); } else { for (i =3D 0; i < ip_cnt; i++) - seq_printf(seq, " %llu", - snmp_fold_field64(net->mib.ip_statistics, - snmp4_ipextstats_list[i].entry, - offsetof(struct ipstats_mib, syncp))); + seq_put_decimal_ull(seq, " ", + snmp_fold_field64(net->mib.ip_statistics, + snmp4_ipextstats_list[i].entry, + offsetof(struct ipstats_mib, syncp))); } kfree(buff); seq_putc(seq, '\n'); --=20 2.39.2